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Full text of "Mimicry in Butterflies."

MIMICRY IN BUTTERFLIES 



BY 

REGINALD CRUNDALL PUNNKTT, RR.S. 

Fellow of Gtmville and Caius College 
Arthur Balfour Professor of (Jcnedc-s in the University of Cambridge 




Cambridge : 

at the University Press 
'9*5 




CAMBRIIK2K UN1VKKS1TY I' 

C. F, C'LAV, MAX*';*;* 
ILontiett; Kl-VITKU LAN!*, F,r 
Etrinburgft ; 100 




Vctft: 0. p. PUTNAM* fluff* 
ntf JlitaMt UACMtf.UN ANtM 

: J. M. IttHT AND Uunji, I tt* 
TUB MAKUXKN-KAHUMHIKl MAlJf 




*f 




PREFACE 

nplHIS little book has boon written in the hope that 
-- it may appeal to Hovoral closncH of readers. 

Not infrequently I have boon ofikcd by friends of 
different callings in life to recommend thorn some book 
on mimicry which shall bo reasonably short, well 
illustrated without being very costly, and not too 
hard to understand. I have always boon obliged to 
tell thorn that T know of nothing in our language 
answering to this description, and it is largely an an 
attempt to remedy this deficiency that the present 
little volume has been written, 

I hope also that it will be found of interest to those 
who live in or visit tropical lands, and are attracted by 
the beauty of the butterfly life around them. There 
are few such countries without sonic of these eases 
of close resemblance between butterflies belonging to 
different families and groups, and it is to those who 
have the opportunity to be among them that we must 
look for fuller light upon one of the most fascinating of 
all nature's problems. If this little book serves to 




PREPACK 

smooth tho path of Home who would brcomi- ac- 
quainted with that problem, ami desire t< * their 
opportunities of observation, the work flint |w* ^mi* fa 
its making will have bwn well repaid. 

To those who cultivate biological t bough* frnm tin' 
more philoBophienl point of vii\v. ! v-nttiri' to IKIJM* 
that what I have written may not ? wit limit HpjwaJ. 
At such a time as the prewnt, bM \vitb iiu|H-nr|tnj; 
changes in tho social fabric*, few thing* an* irr vif U 
than a clear conception of the Henjn* ami uurkingM 
of natural selection. Little rniotigh i* r '-rtnin 
knowledge of tluw* ibingM, and wnall tluutgli the 
butterfly's contribution may l f I tr,t tlmt it. will 
not pass altogether unregartlit!. 

In conclusion I wisli t< cffer my HI wen* llmitli^ f<i 
those who have lielfMnl me in fliffwttt wayn. Mr 
especially are they due to my friendn !>r Karl Jurtlaii 
for tho loan of wmm vnhmble HiH>HitirnH, nml f<* 
Mr T. H. Riches for hw kindly erilieim mi rt 
over the proof-nheets, 

ti i" t 
*.. i . 

February, 



01tAP - PACJK 
I. INTRODUCTORY ....... 1 

II. MiMzoitv BATIBSXAN AND MtfwwcittAN ... 8 

lit. OLD-WORLD MIMIOH . . . , . . jg 

IV. NKW-WOIU,!) MIMWH ...... a? 

V. SoMK rrtlTH'fMMH ....... 50 

VI, "MlMH'RV lUNUX" , ..... (51 

VI J. TllK tlAHK OK j'ttjntio pah/ten ..... 76 

VIII. Tun (!ASK OK /'njiitin jtntt/tcH (emit.) , , . }),'J 

IX. Tan I-JNKMIKH on* nicmgiM.iKH KM 

'"' . * * | ^jt*| 

X. MiMU^RV ANJ> VARIATION . , . , .128 

XI. COW!I,UMON ....... t 1JJ9 

1 If,.) 

11 157 



I XVI AND DKSOIUITXONIHI 
J - V. OJUKNTAL MOTHH AND 

VI IX. AtWJUAN HlITTICHfLIKH. 

X XI H. HOUTII AMKHKIAN 

XIV. H(JAWtt OB* L 
XV. C/KNTRAL ANU KUUTH AMKUKJAN 



XVI. NORTH AMKKKJAN 



183 



*'Th(* prwwwi hy wHMi 
about m imturt' w |rt !' fw! u 
origin of alt Hfx<?if niwl nit Mlnjt*iio 

II, \V 



"With rnimcw, nhcVf il it i* 
that a thing in hlauk, fitut l mijtiirv 
happen to IK* wWtt." 



CHAPTER I 

INTRODUCTORY 

IT in now more than fifty years HI nee Darwin gave 
the theory of natural selection to the world, and the 
conception of a gradual evolution han long ago become 
part of the currency of thought. Evolution for Darwin 
was brought about by more than one factor. He 
believed in the inherited oiTeotH of the UHC and disiiHC 
of parts, and he al> regarded sexual selection OH 
operating at any rate among the higher animaln. Yet 
he looked upon the natural selection of small favour- 
able variations an the principal factor in evolutionary 
change. Since Darwin's time the trend haw been to 
magnify natural (selection at the expense of the other 
two factors. The doctrine of the- inherited effects of 
UHO and diause, vigorously challenged by Wewmann, 
failed to make good its caw*, and it in to-day discredited 
by the. great majority of biologists. Nor perhaps does 
the hypothecs of sexual nelection comtnaiul the 
Hiipport it originally had. At bent it only attempted 
to explain those features, more especially among the 
higher animals, in which the sexes differ from one 
another in pattern, ornament, and the like. With 
the lapse of time there has come about a tendency to 

P. M. 1 




INTKODUfTOHY 



find in natural selection alow n rmupii-ir '\plnmtion 

of the process of evolution, iimi to n^nnl if n* the 
sole factor by which nil evolutionary Hum*' H !nmht 
about. Evolution on thin view w a niinl pn*-inH 
depending upon the *low in*ruiwiltioii fv natural 
selection of email variation*, whirh an- rnon- **r |I<*H 
inherited, till at lawt well-marknl rl^ina* 
brought about Could w* hnve Morr u* ai 
through which a given form IM-M |*;i.^"il 
selection trannformH if into uiiothrr, they wtuM mm- 
stitute a continuoUK wrirj* Ktt'h fht -%-n rHtiirtl 
scrutiny might fail i<> ciwtifigMi-Hti Iwt <-*- it n_v two 
consecutive tornm If th* alight vnrii*ti!i'* nr not of 
service they will get no favour from niitttr.'tl '!-titn 
and so can lead to nothing. Uut if of tti- i the 
struggle for existence natural wl*efiin |ir'iM"t'\r' th*m 
and subsequent variatiotw in the ilirwtitut until 

at length man rocognimw tho atxruitiuUtsnit AM a nw 
form. Moreover when tin* j>erfwi i nn;e 

elaborated natural ftolijction will keep it jwrfi't't ty 
discouraging any tendency to vary from |**rf^tin, 

Upon this view, of which tin* niont ilwfiii.^it!iitI 
protagonist was Wc&tmann, natural *ilwtiin i** tin* wil^ 
arbiter of animal and plant form. Through it awl if. 
alone the world baa come to l what it in. T<i it miwt 
be ascribed all righteouancHti, for it- ttlont* i llw* ntakt*r. 
Such in its extreme form m tin* nuxWn ti*v*lipnu*nt 
of Darwin's great contribution to philomiphy. 

But is it true ? Will natural nerve 

to explain aU I Must all the of 



i] INTRODUCTORY 3 

plants and animals bo supposed to owe their existence 
to the gradual operation of this factor working upon 
small variations ? 

Of recent years there has arisen a school of biolo- 
gists to whom the terms mutationist and Mendolian are 
frequently applied. Influenced by the writings of 
Bateson and de Vries, and by the experimental results 
that have flowed from MendePs discovery in heredity, 
they have come to regard the process of evolution as 
a discontinuous one. The new character that differ- 
entiates one variety from, another arises suddenly as 
a sport or mutation, not by the gradual accretion of 
a vast number of intermediate forms. The white 
flowered plant has arisen suddenly from the blue., or 
the dwarf plant from the tall, and intermediates 
between them need never have existed. The ultimate 
fate of the new form that has arisen through causes 
yet unknown may depend upon natural selection. 
If better endowed than the parent form in the struggle 
for existence it may through natural selection come to 
supplant it. If worse endowed, natural selection will 
probably see to its elimination. But if, as may quite 
possibly happen, it is neither better nor worse adapted 
than the form from which it sprang, then there would 
Htunn to be no reason for natural selection having 
anything to do with the relation of the new form 
to its parent. 

Between the older and the newer or mutationiHt 
point of view an outstanding difference is the role 1 ! 
ascribed to natural selection. On the one view it 

-i > 

4. * a *'% t j 




INTUODUCTOUY 



jril. 



builds up the new variety bit by bit. on tin- nthrr 

the appearance of the new variety it* rntirrly inde- 
pendent of it. From this tbrn* follow* a radical 
difference with regard to thr mrnninft of ml! f IP* 
characters of plants and animate. Thaw wbo 
the all-powcrfulne8 of natural wlif'fion an* 
to regard every character rxbibit<d ly MI animal or 
plant as of service to it in tht* Ktrttj?.li for iv*iHt'nr<-. 
Else it could not have ariarn tbnmgb tbr ojKr/tim of 
natural selection. In other word* ivrry rlwwt^r in 
plant or animal muat t>e adaptive*, i )n f Is** mut Jit 
view this of centra* tioH not follow. If tip- 
character which arisen mdi*(mm!<*nt!y of nnfurut 
tion is neither of service nor dinwrviw t tt |i- 
in the struggle for oxisUmcts tl*n* w*n* no 
why it should not |irwt in jit of natural nrlt- 
In attempting to decide t>otwiHn lh< tw roiil 
views the study of adaptation is wf tin* fin*t imjortflnt i 'i\ 
It was perhaps in conntiction wit It atiA|itation iliat 
Darwin obtained the mewl ntrikin^ i*vilfiitr tn MiijjHrt 
of his theory, and it i cloar from bin writing (bat it 
was in this field he laboured with tnont ilrliglit, Tbo 
marvellous ways in which crtmtttrw* nmy b* nflitjit**l 
in structure and habit for tltti Itfw f,!*y l^itl batt not 
escaped the attention of the* oldtT rtiittiriiiii*i. tIm 
Kay wrote a book 1 upon the xubjtttt in wbtrh li* 
pointed out that all things in tb l;ntvt*ntt% front tin* 
fixed stars to the structure of a bird, or tin* of 



1 The Wisdom o 
1891, 



f God mmi/mtfid in tht 




i] INTRODUCTORY 

a chameleon, or the means whereby some seeds are 
wind distributed, aro "argumentative of Providence 
and Design" and must owe their existence to "the 
Direction of a Superior Cause." Nor have there been 
wanting other authors who have been equally struck 
by the wonders of adaptation. But their studies 
generally led to the same conclusion, an exhortation 
to praise the infinite Wisdom of Him Who in the days 
of Creation had taken thought for all these things. 

The advent of natural selection threw a new light 
upon adaptation and the appearance of design in 
the world, Jn such hooka an thoMo on The, Fertiliza- 
tion of Orchid* and The Forms of Fhwvrn Darwin 
nought to shew that many curiouH and elaborate 
structures which had long puzzled the botanist were of 
service to the plant, and might therefore have arisen 
through the*, agency of natural selection. Especially 
was thi the case in orchids where Darwin waH able 
to bring forward Btriking evidence in favour of regarding 
many a bizarre form of flower as specially adapted 
for securing the benefitB of cross-fertilization through 
the visits of insects. In these and other books Darwin 
opened up a new and fascinating field of investigation, 
and thenceforward the subject of adaptation claimed 
the attention of many naturalists. For the most part 
it lias been an observational rather than an experi- 
mental ntudy. The naturalist in struck by certain 
peculiarities in the form or colour or habits of a species. 
Hin problem is to account for their presences and a# 
nearly ail students of adaptation have been close 



6 INTUOnnTOHY In. 

followers of Darwin, thin giwrnlty iw.w* an inter- 
pretation in temw of natunil wlrrtimi. <ii-if'l thi** 
factor it rcmainn to nhrw thiif th rhnirtT in jn -tit m 
confers some advantage upon tin* iwlivieliml . tli.it 
possess it. For unions it hits a Htililrinn \ lu- ! mum* 
sort it clearly cannot have arisi'ii thrmijsh th- nj<n*fir*n 
of natural selection, However when if roiw* t ibr 
point direct proof of thin t*rt m p-nprally fhihmlt t<* 
obtain. ConBequcritly the work f **! Mtiuli-nt^ of 
adaptation consists in a cJeHertptinn of th^ i-hijr^ri^r 
or characters ftttidiwl t<igether with nui'Ii dri.ul^ *tf 
its life-history an nmy w*em t*i i"Jtr njwn th |iint, 
and a suggcation a to how the fwirtienUr ^itur^rtr-r 
studied may bo of valuo to iff* jKKw*j*n* in thi* ^trtigKlt* 
for existence. In thin wny a l.ly f iuwt 

curious and interesting faeiM hiw !i'ii jlit<-'i! on 
record, and many inffeniouM t!ggt*iiif!w liai'i* twrii 
made as to the poHmblo uc of thin r that i'iinr'i.rr, 
But the majority of worker* have liilw-ii nut unit 
selection for granted and then iiitwwtt^I tli*>i?'Ivrn 
in shewing how tho character)* Htmlie*l hv them nitgiit 

IKE' * 

be of use. Probably there in o Htrurtnre r Jmbtt 
for which it is impofmibta to cic*vii*i* UH'*. aiwt 

the pursuit has doubtless provided many of it* ilf*vf.*n 
with a pleasurable and often ffwcmtttiiig e*eri*i*' f 
the imagination. So it has comt) tiUt>ui that lh* 

1 Ray pves the of an, nlfphMf}t "liwi Wr* 
when he slept to keap hk trunk no <?!WP to tfap i^ruiu^d 
but Air could get in betwixai tlwm," mid r*|4i it AN 
in habit to prevent the ml.ee from emwllng into it 
sagacity and Providence in thii AatnmJ, or *1* i 




i] INTRODUCTORY 7 

instead of being used as a test of the credibility of 
natural selection, serve merely to emphasise the 
ptcan of praise with which such exercises usually 
conclude. The whole matter is too often approached 
in much the same spirit as that in which John Ray 
approached it two centuries ago, except that the 
Omnipotcncy of the Deity is replaced by the Omni- 
potency of Natural Selection. The vital point, which 
is whether Natural (Selection dow offer a satisfactory 
explanation of the living world, is too frequently lost 
sight of. Whether wo are bound or not to interpret 
all the phenomena of life in terms of natural selection 
touches the basis of modern philosophy. It in for tho 
biologist to attempt to find an answer, arid there arc 
few more profitable lincH of attack than a critical 
examination of tho facts of adaptation. Though 
"mimicry" is but a small corner in this vast He-Id of 
inquiry it is a peculiarly favourable one owing to the 
great interest which it has excited for many years 
and the consequently considerable store of facts that 
has been accumulated. If then we would attempt to 
settle this most weighty point in philosophy there m 
probably nothing to which we can appeal with more 
confidence than to the butterfly. 



CHAPTKH II 

MIMICRY BATEHIAS ANI Mfl.M'.HUN 

MIMICRY is a Rfwcial branch of tin* Mwiy f n*bp 
tation. The term han Konwtimr** bwt n-*l tw^ly 
to include cases when* an Anirtm!, mo?*t fr-mi'itt Iv- 
an insect, bears a Btrcmg and oft<it mm! rmiMrlnliIi* 
resemblance to HOJW foattm* of it f * iimiimi;it' ur 
roundings. Many buttfrfUrK with mu^ rlonril np^ 
wonderfully like dead Iivi ; rrrfulii j*jilrr^ w ln'it 
at rest on a leaf look txmrtly ltk* hirtt-lr<j*nin-i{ ; 
"looper" oaterpiliaro mmulaU* miml! ; t 

of the "stick-*' and "leaf- 11 rr in ti 

an indication of their a{f|xarAiu*c*. Ktirli i-iwi**. . 
these, in which the creature exhibit*! ri' f iit!m*'i* t 
some part of its natural Hurrnmuititg** f*h<tiit1 In* 
classified B,S cases of **proUxjtivt rriiwlliiiiri*" lit 
contradistinction to mimicry pwjHr. Striking tr- 
amples of protective roBerttbUnoo art* Ahuittij&nf, itfI 
though we possess little critical knawlt*ti^ of 
acuity of perception in birds and othw iiw 
it is plausible to regard this mwrnbiniiftw iw 
of definite advantage in the* fc*r ^nwttwt\ 

However, it is with mimicry and not with jnt> 
tive coloration in general we mm clltwtlv 




OIL n] MIMICRY 9 

concerned, and tho nature of the phenomenon may 
perhaps best bo made eiear by a brief account of the 
facts which led to tho statement of tho theory. 

In the middle of last century the distinguished 
naturalist, H. W, Bates, was engaged in making 
collections in parts of the Amazon region. He paid 
much attention to butterflies, in which group he 
discovered a remarkably interesting phenomenon 1 . 
Among the species which he took were a large number 
belonging to the group Ithomiinae, small butterflies 
of peculiar appearance with long slender bodies and 
narrow wings bearing in most cases a conspicuous 
pattern (of, PL X, fig. 7), When Bates came to 
examine his catch more closely he discovered that 
among the many ithomiines were a few specimens 
very like them in general shape, colour, and markings, 
but differing in certain anatomical features by 
which the Pierinoo, or "whites,** are separated from 
other groups. Most Pierines are very different from 
Ithomiines. It IB the group to which our common 
cabbage butterfly belongs and the ground colour is 
generally white. The shape of the body and also of the 
wings is in general quite distinct from what it in the 
I'thoinimes. Nevertheless in those particular districts 
certain of tho species of Pierines had departed widely 
from what in usually regarded as their ancestral 
pattern (PL X, fig. 1) and had come to resemble very 
closely the far more abundant Ithomiineu among whom 
they habitually flew (of. PL X, figs. 2 and 3). To 

1 Tram, Linn. doe. vol. 23, 1802. 



10 



MIMK'KY 



- fW 



use Bates* term they "immifkrd" fh< 
and ho Bet to work to doviw an rxpliin 
this could have comr About. Thr nr%^n </ >'/>*<.* 
had just appaml Am! if \v* natural tbat Ha*-? 
should seek to irtterprrt fliis {NTtiliar )hru<>m*-iif!i <m 
the lines then*, kid down. Hmv IUI,H it tlm? ihrw 
Pierincs had contc* to fU*jwtrt w* wiirl\ from th*< v''i*T;il 
form of tho great bulk of thrir rrbitirni^, ni f iiiiniii- 
so closely in apfMwanrr HjHriirM ln-I-ii4,M!i{,' 
entirely different group, wltili* at fit* 1 :w*' inn 
serving tho more dinply wt4x{ mw?*wur;l < 
of their own family ? If I hi* c'tmugi" w.i. t I.*- rr^ : -irI*'<l 
as having come alwut throu^b tb rt^ii-y f it;iftmii 
selection it miwt elrarly IK* of uiv<ufH^r ti tin* 
mimicking fornw ; othrrwiw nut urn) wlrrtjun i-MuM 
not como into operation, Wtiftf lictvautH^ th'ti luivi* 
the Ithomiinea over thi ntajurity of btitu<rlii<M in tho^ 
parts ? They ara witall Iiiw*rf*4, rathr 
build, with ooniparativt?ly wimk IKJWITM f Ui^hi. 
yet so conspicuously ooloumi tlntf, thi\v run Itu 
be mistaken for anything i*tm*. fn Kpit* oi nil 
they are little subject to tin* ! rmmi<.; 

as birds, and Bates attribtitwJ tliw t* fb* 
the jioioes of their &jrct unfmUtulilr. 

to Mm their striking and witoftk'tiiitw juttt4<ru i nf 
the nature of a warning eulomttoin lutvi-rtuaitiK ilwir 
disagreeable propertied to <*iK*mit-.M. A luni 

which had once attempted to imt one wcmfcl Iltitl it 
little to its taste. It would themvforwimi 
the conspieuous pattern with a flavour 



n 



n] BATESTAN AND MULLERIAN 11 

and in future leave such butterflies severely alone. 
Tho more conspicuous the pattern the more readily 
would it bo noticed by the enemy, and BO it would 
be of advantage to the Ithomiine to possess as Htriking 
a pattern as possible. Those butterflies shewing a 
tendency to a more eonapicuouH pattern would be 
more immune to the attacks of birds and so would 
have a better chance of leaving progeny than those 
with a less conspicuous pattern. In this way vari~ 
ations in the direction of greater eonspieuousness would 
be accumulated gradually by natural selecstion, and 
HO would be built up in the Ithomiine. the striking 
warning coloration by which it advertises its disagree- 
able properties. 8uch in the first step in the making 
of a mimicry case the building up through natural 
selection of a conspicuous pattern it) an unpalatable 
sjxuues by means of which it is enabled to advertise its 
disagreeable properties effectively and thereby secure 
immunity from the attacks of enemies which are able 
to appreciate the advertisement, Huch patterns and 
colours are said to be of a "warning" nature. The 
existence of an unpalatable model in considerable 
numbers is the first step in the production of a mimetic 
resemblance through the agency of natural selection. 

We come back now to our Pierine which must 
be assumed to shew the general characters and color- 
ation of the family of whites to which they belong 
(cf. PI. X, fig. 1). Theoretically they are not specially 
protected by nauseous properties from enemies and 
hence their conspicuous white coloration renders 



12 



MIMICRY- 



them especially liable to attack. If, howvver, they 
could exchange their normal drenn for one rewmldiug 
that of the IthomiineH it i clear that they wmiM have 
a chance of being miHtaken for th latter nni con. 
sequently of being left alone, Mor<ovfr. in errtaiti 
cases these Pierine-H Aarr managed to dittrard th^ir 
normal dress and assume thai of th* Ithrtinitii**". On 
theoretical groundH thw tmwt clearly he of a*ivauf;i#i' 
to thorn, and being HO might eonerivaldy Iw\-< nn^'it 
through the operation of natural wlrtnu. Thi 
indeed is what in HUpjWHcd to have taken plun' on the 
theory of mimicry, Thone I*ierineH whi'-h r\hiint<x! 
a variation of colour in the direction of tho IthniiiiifK* 
"model" exeited diHtrunt. in ili<* iiiiis*! f %otiiM>i* 
devourerHj who had learned front ex|Krienei* t 
that particular typo of coloration with a d 

taste. Such Pierinen would therefor.* Imvi' 

better chance of surviving aw! of ttumitg lf|iriitg, 
Some of the oilHpring would exhibit th< vartnticin tit 
a more marked degree and them* again tmuttl in eon- 
sequence have a yat kttter crhanett of mtrviving. 
Natural selection would encourage thorn* vary ing in 
the direction of the Ithomiine modd at the t^^i^iw* w f 
the rest and by its continuouii ojwratian thert* wmiil 
gradually be built up thorn* beautiful of rt**ii- 

blanee which have excited the admiration of natuntiixU. 

Wallace was the next after ti 

himself in mimicry and, from iiw study of tin* butlrfii<i 
of the Oriental regioa l f shewed that In tlik $mrt of 

1 2Voiu. Unn, Soe. vol. XS, 




n] 



BATESIAN AND MULLE'RIAN 



the world too there existed these remarkable resem- 
blances between species belonging to different families, 
Perhaps the most important part of Wallace* con- 
tribution was the demonstration that in some Hpeeies 
not only was it the female alone that "mimicked" 
but that there might bo several different formn of 
female mimicking different models, and in some canes 
all unlike the male of their own Hpeeiea. One of the 
species studied by Wallace, I*<tpitio -poli/tcn, m shewn 
on Plate V. We shall have occasion to refer to 
this case later on, and it in Huflicieul here to call 
attention to the three different forms of female, of 
which one is like the male while the other two resemble 
two other species of Papilio, P. hector and /*. arifttv- 
locMae, which occur in the same localities. Instances 
where the female alone of some unprotected species 
mimicH a model with obnoxioiiH properties are common 
in all tropical countries. It has been HtiggcnttHl that 
thin state of things hat* come about owing to the greater 
need of protection on the part of the female. Hampered 
by the disposal of the next generation the lent* protected 
female would be at a greater disadvantage an e.oni- 
pared with the mimic than would the corresponding 
male whoso obligations to posterity are, more rapidly 
discharged. The view of course makes the assumption 
that the female transmits her peculiar fsropertien to 
her daughters but not to her sons. 

A few years later Trimcm 1 did for Africa what 
Bates had done for America and Wallace for Indo- 

1 Tram. Linn. Hoc. vol. 20, 1870. 



localities (of. p. HO). 

Wo may now turn to one' of the most ingenious 
developments of the theory of mimicry. Not long 
after Bates' original memoir appeared attcnf ion was 
directed to a group of COHCH which could not be 
explained on the simple hyjKvthcsts then* put forward. 
Many striking CONCH of rmmhiam.w had lw*cn adduced 
in which both HpecioH obviously belonged to the pre- 
sumably unpalatable groups. Instances of the* sort 
had been recorded by Bates himself and are ]x*rhaps 
most plentiful in South America between sjctes 
belonging respectively to the Ithomiimu* and Heli- 
coninae. On the theory of mimicry all thn mcmiwrs 
of both of those groupH must be regarded an KfM*ciaily 
protected owing to their conspicuous coloration and 
distasteful properties. What advantage Hunt can an 
Ithomiine be supposed to gain by mimicking a Hcli- 
cordne, or vice vend ? Why should a sjH*eies exchange 
its own bright and conspicuous warning pattern for 
one which is neither brighter nor more conspicuous ? 
To Fritz Holier, tho well-known corwiijKwdtwt of 
Darwin, belongs the credit of having KUggfHUHl a way 
out of the difficulty. Mtiller's explanation turns ujion 
the education of birds. Every year there hatch into 
the world fresh generations of young birds, and each 



ii] BATESIAN AND MULLBRIAN tr> 

generation has to learn afresh from exigence what is 
pleasant to eat and what is not. They will try H 
things and hold fast to that which is good. They will 
learn to associate the gay colours of the Hcliconino and 
the Ithomiine with an evil taste 1 and they will thence- 
forward avoid butterflies which advortiso then-wolves 
by means of these particular colour combinations. Hut 
in a locality where there arc many models, each with 
a different pattern and colour complex, each will have 
to be tested separately before the. unpalalablenesH of 
each is realised. If for example a thousand young 
birds started their education on a population of 
butterflies in which there were five disagreeable* sperien, 
each with a distinct warning pattern, it is dear that 
one thousand of each would devote their lives to the 
education of these birds, or ilvo thousand butterflies 
in all 2 . But if these five spocios, instead of shewing 
five distinct warning patterns, all displayed tho numo 
one it is evident that the education of the birds would 
be accomplished at the price of but one thousand 
butterfly existences instead of five. Even if owe of 
the five species were far more abundant than the* 
others it would yet be to its advantage that the oilier 
four should exhibit the aamo warning pattern. Kveii 
though the losses were distributed pro rala. the inon* 
abundant species would profit to some, extent, Kor 

1 In attributing thin quality to Iho IwfctorlHt'M m <iumtum I m 
merely Htating what iw hold by tho nupporltw of tho mimic.ry th*ry. 
I know of Hcarcoly any ovidonco tnthor for or ngmnt tho upjKiitint, 

2 It JH aHHumod that tho intolliffonoo of th hinln i nut'h tlmt th^y 
can loarn a pattern, after a single dwagrwsablt) oxpcrkwct* of it. 




MIMICRY foi. 

the less abundant the gain would of emtrne be 

relatively greater. Theoretically therefore, all of flit* 
five species would profit If in of five 

warning patterns they exhibitor! but * owe in 

common. And since it profitable to nil efwrerned 
what more natural than that it- be 

about by natural ! 

Muller's views are now widely accepted by 
of mimicry as an explanation of rtirimw 

where two or more evidently Hperiiv* rlfwly 

resemble one another. Indeed the tendency in r<*<ut 
years has been to see Mttllerian mimicry t'verywlnTe, 
and many of the inntance which 
as simple Bateuan have now to 

this category. The hypothemn w, of emtrne, 
what appears to man to bw the 
of young birds under eertatn conditiotft*. XM 
knows whether young birdn acttially clo in the 

way that they are lupfMuwcl to. In tbe f 

any such body of the 

cannot rank as more than a 

as will appear later, it fa o\nm to on 

general grounds, 

Perhaps the contribution to tbe of 

mimicry which of the 

that ol Erich Haas 1 , to f 

matters must alwaye lie & 

It was the first and still the of 

general scope, Sine tiny nf 




n] 



BATESIAN AND MOLLERIAN 



fresh Instances of mimetic resemblance have been, 
recorded from all the great tropical areas of the world, 
and the list is being added to continually. Most 
active in this direction ie the Oxford School under 
Professor Poulton to whose untiring efforts are largely 
due the substantial increases in our knowledge of 
African butterflies contributed by various workers in 
the field during the past few years. Whatever the 
interpretation put upon them, there can be no question 
as to the value of the facts brought together, more 
especially those referring to the nature of tho families 
raised in captivity from various mimetic forms* With 
tho considerable additions from Africa 1 during the 
past few years several hundreds of cases of mimicry 
must now have been recorded. Some of the best 
known and most striking from among these will be 
described briefly in tho next two chapters. 

1 Tho African mimetic butterfliea have been recently monographed 
by Eltringham in a large and beautifully illuitrated work African 
Mitrmtic Butterftim, Oxford, 1910. 




CHAPTER 



OLD-WORLD MIMICS 

THE earlier naturalists who Btudifd buttwfiit** 
made use of colour and pattern very largely I 
and classifying their specimen!, iii*wing tin* 

same features in these gtmer&Hy 

together without further question, if tluy 

-were known to oome from tho locality. In 

looking through old collection* of from tlw* 

tropics it is not infrequent to find the collector 
was deceived by a mimetic into model 

and mimic together, During the kit however, 

more attention was paid to the 
with the result that their WM 

upon a basis of structure* As in all of tli* twit 

certain features are to 

constancy and partly for their tlte 

being arranged according m to they 

these features or not. Everybody that tlic 

butterflies as a group are from the on 

the ground that their art oiwb at the 

end, while those of the moth are 
and taper to a fin point The 




OH. til] 



OLD-WORLD MIMICS 



19 











Figs. 1~8. Terminal portion of front logs of butterflies belonging 
to different famiUon. (After Eltringham.) 

(Nymphalidae). 
( ) 
(Eryoinidae). 



1, Hypolimneu muippw, 
<u< a ii 



3. Abisara mvilri, ? 

4. T 

6, Lycaena ierw, 9 
(i. Gupido got, if 

7, Oanorw retpae, tt 

8, Papilio eekerit)ide8 t ? 



( Lyoaeaidao), 

( ). 

(Pierfdae). 

(Papilionidao). 



22 



20 



OLD-WORLD MIMICS 



fcii. 



may be subdivided into five main group* or 
according to the structure of the first of their thrw 
pairs of legs. In the Papiiionidae or "awallow-tiiilji," 
the first pair of legs is well develojjed in both 
(Fig. 8). In the Pieridae or "whiten," the front 
are also similar in both but the*, dawn an liilit! 

and a median process, the empodhitn* Is found bit 
them (Fig. 7). In the remaining thrw families tin* 
front legs differ in the two The c*f thr 

Lycaenidae or "blues** ha?e weU-devi?Iopl front. 
in which the tarsus is terminated by clpfir 
(Pig. 5), whereaa in the the terminal of 

leg, or tarsus, is tmjointed and with but a 

single small claw (Fig* 8)* Thin tif thr 

front legs has gone somewhat further in th 
(Figs. 3 and 4), a family for tin* 

of rather small butterflies and 
of South America. In the of the Nym 

phalidae the reduction of the front is 
in both sexes. Not only are 
in the other groups, but .aw in tli 

as well as in the male (Figs. 1 and 2)* 

Though the structure of the fore in t!w 

character specially for 

families from one another, it it of 
that they differ from one in 

distinctive features* Tli of tht 

for exatnple hangs by Uw 

1 Omitting the wMoh into a 




m] OLD-WORLD MIMICS 21 

tail, whereas in the Pieridae and Papilionidae meta- 
morphosis takes place with the chrysalis attached by 
the tail but supported also by a fine girdle of silk 
round the middle so that the head is uppermost. The 
larvae also afford characters by which some of the 
families may be distinguished those of the Papilionidae 
for example having a process on the back which canu 
be extruded or retracted. 

Owing to the great size of the family of the Nym- 
phalidae, in which the number of species approaches 
5000, it is convenient to deal with the eight sub-groups 
into which it has been divided. The characters serving 
to mark off the sub-groups from one another are various. 
Sometimes it is the minuter structure of the tarsus, at 
others the form of the caterpillar or the chrysalis, at 
others the arrangement of the nervures that form the 
skeleton of the wing. Into these systematic details, 
however, we need not enter more fully here 1 . What is 
f important from the standpoint of mimicry is that 

these divisions, made solely on anatomical structure, 
correspond closely with the separation of models from 
mimics* Of the eight sub-families into which the 
Nymphalidae arc divided four, viz. the Danainae, 
Aeraeinae, Heliconinae, and Ithomiinae, provide models 
and some, but far fewer, mimics ; two, the Satyrinae 
and Nymphalinae, provide many mimics and but few 
models, while two groups, the Morphinae and Bras- 
solinae, practically do not enter into the mimicry story. 

1 The classification, adopted fa that used by Dr Sharp hi the 
"Cambridge Natural History," Inmtt8 t vol. 2, 100 L 



OLD-WORLD MIMICS 



[CTH, 



Simple mimicry, explicable, at any rate* m thoory, 
on the lines laid down by Bates, IB a phtnom-miii of 
not infrequent occurrence in tropical conntrirK, though 
rare in more temperate land. In each of fl thnv 
great divisions of 'the tropical world we find rwfnin 
groups of butterflies serving aa rtioclrK ami hrin^ 
mimicked by butterflies belonging iw a rule* to quit*' 
Afferent groups. Speaking generally thr modi*!* cf 
any given region are confined to a few groups, while* 
the mimics are drawn from a greatw ntimbrr. In Awn 
the' principal models belong to tin* Danaiw*. thu 
Euploeines, and to a group of swallow-tail* wliirli from 
the fact that their larvae feed on tin* /Im- 

tolochia plant are generally diatinguwhwl m thu " I*wof t 
eaters/' or Pfarmacophagw grotip. Of tliiw tlir 
Danaines and Buploeinea ara uric! lwv* 

much in common. They ara umsaliy iitift*rllit-ii til 
medium size, of rather flimsy build and with * onn- 
what slow and flaunting flight. In howwr. of 

their slight build they are wid 

tenacious of life. Moat me by 

simply nipping the thorax* in a 

and the fly never But the 

treats a Danaid in a w&y that kill 

butterflies is as Hkely as not many to 

it stiU alive in MB collecting or in tin* to 

which it may have bec 
They give one the of 

more "rubbery" in tttts of 

Lepidoptera. Moreover* the of 



Ill] 



OLD- WORLD MIMICS 



23 



to be more oily and less easily dried up. In general 
colour scheme they vary a great deal. Some, such as 
Danais chrysippm (PL IV, fig. 1), are conspicuous 
with their bright fulvous-brown ground colour and the 
sharp white markings on the black tips of their fore 
wings. Others again such as Danais septentrionis (PL I, 
fig, 3), with a dark network of lines on a pale greenish 
ground, are not nearly so conspicuous. Of the Euploe- 
ines some have a beautiful deep blue metallic lustre (c 
PL II, fig. 4), though many are of a plain sombre 
brown relieved only by an inconspicuous border of 
lighter markings (cf. PL I, fig. 10). 

Both Danaines and Euploeines serve as models for 
a great variety of species belonging to different groups. 
Danais septentrionia (PL I, fig. 3) is a very abundant 
spccicB in India and Ceylon, and in the same region 
there are several other very similar species. Flying 
with them in Northern India are two species of Papilio, 
P. macarem and P. xenodes (PL I, fig. 4), which 
resemble these Danaids fairly closely. In Southern 
India and Ceylon one of the two forms of Papilio elytia 
(PL I, fig. 7) is also regarded as a mimic of these 
Danaids. In the same part of the world there is a 
Pierine of the genus Pareronia, whose female is very 
like these Danaines on the upper surface (PL I, fig. 1). 
The male of this Pierine is quite distinct from the 
female (PL I, fig. 2), 

The common Danais chrysippw (PL IV, fig. 1), 
found in this region, has been described as probably 
the most abundant butterfly in the world, and serves 




OLD-WOBLD 



[CH. 



as a model for several species belonging to different 
groups. It and its mimics will, however, be ctacritied 
in more detail later on. Mention must alao be made* 
of the striking case of the Danaid, and 

its Papilionine' mimic P. agettor from Sikkim (1*1. II, 
figs. 2 and 3). In both species the fore wingM are 
pale blue broken by black; white the hind are 

pale with a deep outer border of runty red. Not only 
in colour but also in the swallow-tail a 

remarkable resemblance to tho Danatd, (\ m 

also mimieked by a rare Nymphaline AV/i/i* t miton*, 
which exhibits the same striking colour m very 

different from that of most of its 

No less remarkable are some of the in which 

the Euploeines servo as model*. M. fur 

example, is mimicked by the Pnpitfa wrw/tur, 

and a glance at Figs, 8 and 9 on Plate II 
how well this butterfly it* name. 

rhadamanthus also aa a mode! for one of tin* 

several forms of famala of the Hyttifiitalitif* i<|*rii*H 
JEuripm Imliih&rsm. In tin* *ttm n 

different in appearance a ftiittg 

among butterflies serving M In of ijii4t*f ic* 

resembliwaoe* Such a m lit Kupfaa 

mAdbw, the male being brown nit It a 

beautiful deep blue suffusion, the k 

rather lighter mieot with lew of the blue 
and with hmd winp with 

(PL II, figs, 4 aad 5). It in to fittci 

itymnias maldw, a &rtyrid which this 



m] OLD-WORLD MIMICS 25 

shews a similar difference in the two sexes (PL II, figs. 
8 and 7). 

It is remarkable that similar sexual difference is 
also shewn by the rare Papilio paradoxm, the two 
here again mimicking respectively the two sexes 
of Euploea mukiber. 

Many of the Euploeines, more especially those from 
Southern India and Ceylon, lack the blue suffusion, and 
are sombre brown insects somewhat relieved by lighter 
markings along the hinder border of the hind wings, 
Euploea core (PL I, fig. 10), a very common insect, is 
typical of this group. A similar coloration is found 
in one of the forms of Papilio dytia (PL I, fig. 8) 
from the same region as well as in the female of the 
Nymphaline species Hypolimnae bolina (PL I, fig, 6), 
The male of this last species (PL I, fig, 5) is quite 
unlike its female, but is not unlike the male of the 
allied species, IL mwippus, which it resembles in the 
very dark wings each with a white patch in the centre, 
the junction of light and dark being in each case 
marked by a beautiful purple-blue suffusion. There 
is also a species of Elymnias (E. singhala) in this part of 
the world which in general colour scheme is not widely 
dissimilar from these brown Euploeas (PL I, fig. 9). 

The third main group of models characteristic of 
this region belongs to the Papiiionidae. It was pointed 
out by Haase some 20 years ago that this great family 
falls into three definite sections, separable on anatom- 
ical grounds (see Appendix II). One of these sections 
h termed the Pharmacophoffug or '* poison-eating ** 




OLD-WORLD MIMIC'S 



(cit. 



group owing to the fact that the larvae, fcn-cl on the 
poisonous climbing plants of the gemm Arisfotnrfritt. 
It is from this group that all Papilio* which nervr iw 
models are drawn. No mimtcH of other unpalatable 
groups such as Danainea arc to IK* found among tin 1 
Oriental Poison-eaters, In the other two Hix*tif>iu< of 
the genus miznios are not infrequent (rf. Apjiendix II), 
though probably none of them nerve iw model*. To 
the Pharmacopnagus fp*owp tin* giwinw 

insects of IndoMalaya-~the magnificent Ornitiioptfnt, 
largest aad most splendid of butterf)}(*<H. ft i not n 
large proportion of the mcmt>rrH of the group which 
serve as models, and these on the whole an* tin* 

smaller and less conspicuous form*. In nil 
mimic, when a butterfly, to thtt Pajntw 

of the three sections into which divided 

family (of. Appendix II). PapiUa f !*l V, 

fig, 6), for example, ia mimiokod by ft form f 

Papilio pofytes, and the of 

widely spread model are by 

those of the equally wide mtmk*. For 

range from Western India to 

Another poison-eater, P. a, mode! for 

one of -yie femalw of the common /*. It w 

ourions that in of the 

serve as models the are In 

pattern, and we mimicked by tmiy 

of the other two PapiMo in tlit* Ortu- 

thoptera, which also to the tltc 

difference between the w 



HI] OLD-WORLD MIMICS 27 

Though the Pharmacophagus Papilios are mimicked 
only by other Papilios among butterflies they may 
serve occasionally as models for certain of the larger 
day-flying moths. Papilio polyxenus, for example, is 
mimicked not only by the unprotected P. bootes but also 
by th moth JSpicopeia polydora (PL III, figs. 5 and 0). 
Like the butterfly the Epicopeia, which is compara- 
tively rare, has the white patch and the outer border 
of red marginal spots on the hind wing. Though it 
is apparently unable to provide itself with an orthodox 
tail it nevertheless makes a creditable attempt at one. 
There are several other oasoa of mimetic resemblance 
between day-flying moths and PharmacophaguB swal- 
low-tailsthe latter in each case serving as the model. 
Rarely it may happen that the role of butterfly and 
moth is reversed, and the butterfly becomes the mimic. 
A very remarkable instance of this is found in New 
Guinea where the rare Papilio laglmmi mimics the 
common day-flying moth AUidis agaffiyrsus, Viewed 
from above the resemblance is sufficiently striking 
(PL III, figs. 1 and 2), but the most wonderful feature 
concerns the underneath. The ventral half of the 
moth's abdomen is coloured brilliant orange. When 
the wings are folded back they cover and hide from 
sight only the dorsal part of the abdomen, so that in 
this position the orange neutral surface is conspicuous. 
When, however, the wings of the butterfly are folded 
they conceal the whole of the abdomen. But the 
butterfly has developed on each hind wing itself a 
bright orange patch in such a position that when the 






28 OLD-WORLD MIMICS [OH. 

wings are folded back the orange patch lies over the 
sides of the abdomen. In this way is simulated the 
brilliant abdomen of the moth by a butterfly, in which, 
as in its relations, this part is of a dark and sombre 
hue. 

A few models are also provided in the Oriental 
region by the genus Delias, which belongs to the Pier- 
ines. A common form, Delias eucharis, is white above 
but the under surface of the hind wings is conspicuous 
with yellow and scarlet (PL II, fig. 1). It has been 
suggested that this species serves as a model for another 
and closely allied Pierine, Prioneris sita, a species 
distinctly scarcer than the Delias. There is some 
evidence that the latter is distasteful (cf. p. 115), but 
nothing is known of the Prioneris in this respect. 
Other species of Delias are said to function as models 
for certain day-flying moths belonging to the family 
Chalcosiidae, which may bear a close resemblance to 
them. In certain cases it may happen that the 
moth is more abundant than the Pierine that it re- 
sembles 1 . 

Tropical Africa is probably more wealthy in mimetic 
analogies than Indo-Malaya, and the African cases 
have recently been gathered together by Eltringham 
in a large and beautifully illustrated memoir 2 . The 
principal models of the region are furnished by the 
Danainae and the allied group of the Acraeinae. Of 
the Danaines one well-known model, Danais chrysippus, 

1 Cf. Shelf ord, Proc. ZooL Soc. 1902. 

2 African Mimetic Butterflies, Oxford, 1910. 



in] 



OLD-WORLD MIMICS 



29 



is common to Africa and to Indo-Malaya. Common also 
to the two regions are the mimics, Argynnia hyperbim 
and Hypolimnoa misippm (cf. PL IV, figs. 3 and 7). 
The case of the last named is peculiarly interesting 
because it presents well-marked varieties which can 
be paralleled by similar ones in D. chrysippus. In 
addition to the typical form with the dark tipped 
foro wing relieved by a white bar there is in each species 
a form uniformly brown, lacking both the dark tip and 
the white bar of the fore wing. There is also another 
form in the two species in which the hind wing is 
almost white instead of the usual brown shade. In 
both species, moreover, the white hind wing may be 
associated either with the uniformly brown fore wing 
or with the typical form, There is also another common 
African butterfly, A craea encedon, in which these different 
pattern* ar closely paralleled ( cf . PL IX ). Several other 
species of butterflies and a few diurnal moths bear a 
more or close resemblance to D. chrysippm. 

Danalne butterflies with the dark interlacing lines 
on a greenish-blu ground, so characteristic of the 
Oriental region, are represented in Africa by the species 
Danati petiverana, (PL VI, fig. 1) ranging across the 
continent from Sierra Leone to British East Africa. 
A common Papilio, P. leonidas (PL VI, fig. 2) has a 
iimikr extensive range, and has been regarded as a 
mimic of the Danaine. In 8, Africa P. leonidas is 
represented by the variety braMdaa in which the white 
are reduced and the blue-green ground is lacking. 
bears a strong resemblance to the tropical 



30 OLD-WORLD MIMICS [OH. 

Danaine Amauris hyalites (PL VI, fig. 3) of which it 
has been regarded as a mimic. It must however be 
added that it is only over a small part of their respective 
ranges, viz. in Angola, that the two species are to be 
met with together. 

The butterflies belonging to the genus Amauris are 
j among the most abundant and characteristic Danaine 

: models of Africa. Some of the black and white species 

such as A. niavius (PL VIII, fig. 6) are conspicuous 
insects in a cabinet. Others again, such as A. echeria 
(PL VIII, fig. 7), are relatively sombre-looking forms. 
Among the best known mimics of the genus is a species 
! of Hypolimnas* H. dubius. This interesting form is 

polymorphic and mimics different species of Amauris. 

The variety wahlbergi, for example, is very like A. 

j niavius, while mima strongly resembles A. echeria 

5 (PL VIII, figs. 8 and 9). It was at one time supposed 

that these two varieties of Hypolimnas dubius were 
different species and the matter was only definitely 
I settled when the two forms were bred from the eggs 

I of the same female. Other mimics of Amauris are 

^ found among the Papilios and the Nymphaline genus 

\ Pseudacraea. 

j But among all the mimics of Danaines in Africa 

! and elsewhere Papilio dardanus is pre-eminent, and 

I has been described by more than one writer as the 

most important case of mimicry in existence. Not 

only does it shew remarkable resemblances to various 

1 These African species of HypoUnmas are frequently referred to the 
genus IBuraMa. 



HI] 



OLD-WORLD MIMICS 



31 



Danaids, but it presents features of such peculiar 
interest that it must be considered in more detail 
PapiUo dardanm in its various sub-races is spread over 
nearly all the African continent south of the Sahara. 
Over all this area the male, save for relatively small 
differences, remains unchanged a lemon-yellow insect, 
tailed, and with black markings on fore and hind wings 
(PL VIII, fig. 1). The female, however, exhibits an 
extraordinary range of variation. In South Africa she 
appears in three guises, (1) the eenea form resembling 
Amauris echeria, (2) the hippocoon form like Amauris 
niavius, and (3) the trophonius form which is a 
close mimic of the common Danaia tfvryaippus 1 * 
Except that cenea does not occur on the West Coast 
these three forms of female are found over almost all the 
great continental range of dardanus and its geographical 
races. Northwards in the latitude of Victoria Nyanza 
occurs a distinct form of female, planemoides, which 
bears a remarkable resemblance to the common and 
distasteful Plan&ma poggei f and is found only where 
the latter is abundant. All of these four forms are 
close mimics of a common Danaine or Acraeine model 
Other forms of female, however, are known, of which 
two, dionysus and trimeni, are sufficiently distinct and 
constant to have acquired special names. Dionysus 
may be said to unite the fore wing of the hippocom 
form with the bind wing of the trophonius form, except 
that the colour of the last part is yellow instead of 

1 Corresponding to the donppus form of D. Gkrygippus (of. PI. IX) 
there is a rare form of irophoniw knowa as dorippoid&s. 



32 



OLD-WORLD MIMICS 



[CH. 



bright brown. It is a western form and is -unlike any 
model. Trimeni also is unlike any model but is 
of peculiar interest in that it is much more like the 
male with ' its pale creamy-yellow colour and the 
lesser development of black scales than occurs in 
most of the forms of female. At the same time the 
general arrangement of the darker markings is on the 
whole similar to that in the hippocoon and in the 
trophonius form. Trimeni is found on the Kikuyu 
Escarpment, near Mt Kenia, along with the four 
mimicking forms. 

Continental Africa, south of the equator, has 
produced no female similar to the male. But in 
Abyssinia is found another state of things. Here, so 
far as is known, occur three forms, all tailed, of which 
one is similar hi general colour and pattern to the male, 
while the other two, niavioides and ruspina 1 , resemble 
respectively a tailed hippocoon and a tailed trophonius. 
Lastly we have to record that Pctpilio dardanus is 
also found as the geographical race humbloti on Comoro 
Island, and as meriones on Madagascar. In both 
forms the females are tailed, and resemble the males. 

From this long series of facts it is concluded that 
the male of P. dardanus represents the original form 
of both sexes. On the islands of Comoro and Mada- 
gascar this state of things still survives. But it is 
supposed that on the African continent existed enemies 
which persecuted the species more than on the islands 

1 These two forms are figured on Plate 10 of Eltringham's African 
Mvmetic Butterflies* 



in] 



OLD-WORLD MIMICS 



33 



and encouraged the development of mimetic forms 
in the female. The original female stiU lingers in 
Abyssinia though it is now accompanied by the two 
mimetic forms niavioides and ruspina. Over the 
rest of the area occupied by dardanus the females 
are always tailless and, with the exception of trimeni 
and dionysm t wonderfully close mimics. Trimeni, 
the intermediate form, provides the clue to the way 
in which the mimetic females have been derived 
from the male, viz. by the prolongation across the 
fore wing of the dark costal bar already found in the 
females of the Madagascar and Abyssinian races, 
by the deepening of the dark edging to the wings, 
and by tho loss of the tail. Through the gradual 
accumulation of small variations trimeni came from 
the male-like female, and by further gradual accumula- 
tion of small favourable variations the mimetic forms 
camo from trimeni. South of the equator the male- 
like form and the intermediate trimeni have dis- 
appeared owing to the stringency of selection being 
greater. Moreover the likeness of mimic to model 
is closer than in tho north, a further proof of the 
greater stringency of natural selection in these parts. 
Such in brief is the explanation in terms of mimicry 
of the remarkable and complex case of dardanus* 

Although the Euploeinae are not represented on 
tho African continent, it is the headquarters of another 
distasteful family of butterfliesthe Acraeinae which 
is but sparingly represented in the Oriental region 1 . 

1 Acraw violae, the only repremtetive of tho group in S. India 
p. M. 3 



34 



OLD-WORLD MIMICS 



fen. 



Of smaller size than the Danainos they are charac- 
terised, like this group, by their tenacity of life and 
by the presumably distasteful character of thoir 
body juices. They are said also to pomeon an anViuitvc 
odour apparently exuded through the thorax, Tho 
majority of the members of tho group fall into the 
two genera Acraea and Pfanr.tna. iSjKH?ie of Arrow 
are on the whole characterised by their general bright 
red-brown colour and by the conHpicuottn hlark H|n>ta 
on both fore and hind wings. A typical Acractm* 
pattern is that of Acraea (PL VI t fig. 7j which 

is mimicked remarkably closely by the Nymphalina 
Pseudacmea boisduvati and by the Swallow-tail /*|iilio 
ridkyanus (PL VI, figa, 5 and 0), 

In the genus Plamnm the spot* nrft ax a rule 
and clustered near the body f while on both fore and 
hind wings there is a tendency to develop clear * wide 
band-like areas of oranges or white (of. PL VII). 

Like the Acraeas the Planemau art |iriiicji|mtly 
mimicked by species of and of 

Some of the cases of between 

and Pseudacmea are among the known. 

Pfanema macansta is one of comparatively 

instances in which a model a 

in the pattern of the two The on tliii 

fore wing of the male is in the 

female it ig somewhat different in and, like the 

area on the hind wing, is white (of. PL VII, lip, 1 and 2). 

attd Oeybn, to a vey tbundMit . 1 1 

be said that it fe detoltoly ndmfoktd by any itti* tvtcKt. 



in] 



OLD-WORLD MIMICS 



35 



Pseudacraea eurytm hobleyi (PL VII, figs. 6 and 7) shews 
a similar difference in the sexes, the male and female of 
this species mimicking respectively the male and female 
of Planema macarista. The case is made even more 
remarkable by the fact that both of the sexual forms 
of Planema macarista are mimicked by the Satyrine 
Mymnias phegea (PI. VII, fig. 9), though in this species 
either the black and white, or the black, white, and 
orange form may occur in either sex. Among the best 
Papilionme mimics of the Planemas is Papilio cynorta 
whose female is extraordinarily like the common 
Planema epaea (PL VII, figs. 5 and 10). The re- 
semblance of the planemoides female of P. dardanus 
to P. poggei has akeady been noticed. 

A striking feature of the African continent is 
the frequency with which mimetic forms are found 
among the Lycaenidae. As a rule the "blues " rarely 
exhibit mipaetie analogies, but in Africa there are 
several species, especially those of the genus Mim- 
acraea, which closely resemble Acraeines. Others again 
bear a marked resemblance to certain small Pierines, 
CitronopMla similia from S. Nigeria for example 
being extraordinarily like the common Teriaa brigitta, 
a small bright yellow Pierine with black-edged 
wings. 

A remarkable feature of the African continent 
is the absence of the Pharmacophagus Swallow-tails. 
Of such Papilios as exhibit mimicry, and as compared 
with the total number of the group present the pro- 
portion is large, the majority resemble one or other 

32 



36 OLD-WORLD (fit, in 

of the frw miPlt AN 

P, ?* mi 

or a Planemold 

As in the tlw 

do not oflfer f 

is, In 



authors an mcxli'j'i ?r ilJfl 

a **** Phnfi*nw. llwt * ttMihrr 

nor off**? * iHrk*J Intrt?fi*<' in 

Lw s**-* if a- tioiibffiftl 

Africa of*r* (>** 44f ( 'iii r* til 

in which pl.i% A j>*ti. Th 

spiottot /il*liA |*!*'ifn ii mi 

aad with ite iwl 

broken by it I* m- tit iJw 

itete Among tb** A ! r 

to It are tk* rri*|,ti, nit4 tin* 

- w 




CHAPTER IV 

NEW-WORLD MIMICS 

all the continents South America affords the 
greatest wealth of butterfly life, and it is in the tropical 
part of this region that many of the most beautiful 
and striking cases of mimicry are to be found. Viewed 
as a whole the butterfly population presents several 
features which serve to mark it off from that of the 
other two great tropical areas. In the first place 
the proportion of gaily coloured forms is higher. 
Bright red, yellow or fulvous brown contrasted with 
some deep shade approaching black form the dominant 
notes. Sombre coloured species are relatively scarcer 
than in the Oriental and African regions. In the 
second place when looking over collections from this 
part of the world one cannot help being struck by the 
frequency with which similar colour combinations 
occur over and over again in different as well as in 
the same groups. Now it is a simple scheme of black 
with an oblique scarlet band upon the fore wings- 
now an arrangement with alternating stripes of bright 
brown and black relieved with patches of clear yellow 
now again a scheme of pure transparency and black. 



NEW-WORLD MIMICS 




[CH. 



In connection with it there is a feature of peculiar 
interest in that the transparent effect ia not always 
produced in the same way. In the Ithomiiiuw uc?h 
as Thyridia, where there are normally two kind* of 
scales, the wider ones for the most part lone their 
pigment, become much redacted in ste and on 

the shape of a stumpy V (PL XIV, fig. 3). AIno they 
stand out for the most part more or few at right 
to the wing 1 , and the neck by which they are joined 
to the wing membrane is very ahort. The longer 
and narrow form of also tend to their 

pigment and become reduced to fine In J%** 

morphia the scales, which are of ones nort, arc* 
reduced in size though apparently not in number. 
Like the wider scales of the Thyridia they tend wmte- 
times to project at right to the wing membrane. 

though not to the same extent a in the Ithomitne ; 
possibly because the neck of the w not no 

short. As in Thyridia reduced 

their pigment except in the tmaaition round 

the borders of the transparent In 

there is a difference, The are not to 

the same extent in point of Their Am 

longer as in normal and they lie Dut on the 

wing membrane* The majority of the mi lit 

the preceding losa their pigment, but 

up with them is a certain proportion, 

1 These dMortptiooi n from 

I owe for the most part to the of Dr I 

hadea opportunity of exaaatotog 



IV] 



]STEW-WOKLB MIMICS 



in which the pigment is retained. In Castnia and in 
Anthomysa the scales on the transparent parts which 
are without pigment are also somewhat reduced in 
size, being stumpier than the normal ones. At the 
same time they tend to stand out at right angles 
to the wing membrane 1 . The neck here again is 
shorter in the transparent than in the pigmented 
scales. A good deal of stress has been laid upon 
this case by some supporters of the theory of mimicry, 
since it is supposed to shew that a similar effect can 
be brought about in a variety of ways ; consequently 
the existence of this assembly of similar transparent 
forms belonging to various families cannot be put 
down as due to the effect of similar conditions, but 
must be regarded as having arisen in each instance 
in a different manner through the independent action 
of natural selection 2 . It is doubtful, however, whether 
such a conclusion necessarily follows from the facts. 
'In all of the cases the process would appear to be 
similar: loss of pigment, reduction in the size of th 
scales, and eventually a tendency for the scales to 
stand at right angles to the wing this last part of 
the process apparently depending upon the reduction 
of the neck of the scale. It has been said that greater 
transparency is brought about by the scales standing 
out at right angles in this way, but as the scales them- 

1 This IB more marked in Qmtma, than, in Anthomysa, It appears 
to bo a peculiarity of many members of the genus Oastnia that the 
BoaleB do not lie BO tight fti generally in moths. Owing to this, some 
of the largo whole-coloured apeoiei have a somewhat fluffy look, 

2 Of, Poultoa, Etaayt on Evolution, 1908, pp. 264-8. 



42 NEW-WORLD MIMIC'S 

selves are already transparent then? would Apfxw 
to be no reason why this should be HO. Of rourw 
the process has not proceeded in all of the form* 
to the same extent. There, in le.a*t change in //wi 
where the scales are not much reduml in * and 
where a fair proportion are still pigment**!. Then* 
is probably most in an Ithomiine nueh m Tht/riititt, 
where the scales are not only small and entirely wit bout- 
pigment, but also are for the trt nfekhw m 
that they stand out at right to the wing. H living 
regard to the faet that widely 
with different types of formed the 
points, -the final results do not to prwlwli* the 
supposition that the transparency ban through 
a similar process in all of them, 

It is somewhat remarkable* that no Batyriw* txh*htt 
mimicry in S. America, in spite of the that trait*- 
pareney of the winp, as in HO many of tftit 
of this region, is quite common in tb On 

the other hand the relatively number of 

or less mimetic Hermes is a tif H. 

America, For the to tli 

genera Dimorphw and Perrhybri*, 
yellow, black, and brown Ithomitm**, 

though Borne of the former Me of the 

small transparent Ithomlines, of tito 

of Pereute with their ground and Ui 

bright red bar the fore (PL XI, %* S) 

resemble HeUcomm m iJm 

But some of the 



IV] 



NEW-WOKLD MIMICS 



mimics are several forms belonging to the genus 
Arohonias (PL XI, fig. 10) which exhibit the simple 
and striking arrangement of black, red and white 
so characteristic of the Swallow-tail Poison-eaters of 
S. America. They form one of the rare instances of a 
Pharmaeophagus Papilio being mimicked by a butterfly 
which does not belong to the Swallow-tail group, 

As everywhere in the tropics the Papilios of S. 
America supply a goodly proportion of the mimicry 
eases. A few, such as P. zagreus (PL X, fig. 8), 
enter into the black-brown and yellow Ithomiine- 
Heliconine combination ; P. euterpinus resembles Heli- 
conius melpomene (PL XI, fig. 5) ; P. pausanias is like 
Heliconius sulphurea (PL XI, figs. 1 and 2). But this 
practically exhausts the list of Papilios which mimic 
Holiconinos and Ithomiines. The great majority of 
mimicking Swallow-tails in S, America find their models 
among the Poison-eaters of their own family, offering 
in this respect a contrast to those of Asia where the 
majority of models are among the Danaines and 
Euploeines, and of Africa where they are exclusively 
Acraeines or Danaines. 

The Poison-eaters of S. America fall into two well- 
marked groups which we may call the red-spotted 
and the dark green groups respectively. The red 
spotted group form a remarkably compact and 
uniform assemblage. The general ground colour is a 
deep black-brown (PL XI, figs. 8 and 9), the hind wings 
are almost invariably marked with red near the centre 
or towards the outer margin, and the fore wing may 



44 



NEW-WORLD MIMICS 



[CH. 



or may not bear a patch which m generally whitifth 
in the female, though often of a brilliant blue or 
in the male. This simple colour scheme with varia- 
tions runs throughout about three-quarters (norm* 
40 species) of the Poison-eaters, The name general 
colour scheme is also found in about two doxen 
of the unprotected Swallow-tails. Aa the total number 
of the unprotected is placed by Heitz at lew 

than 100 this means that fully ono-quartcr of them 
fall into the general colour schema adopted by the 
majority of the Poison-eatera. In many the 

resemblance between mimic and is HO a* 

to have deceived the most export (sntomolojtt'Htu Jiefore 
the structural differences between tlia had 

been appreciated (of. Appendix II). Tim in 

further complicated by the fact that {wiynwrphwm m 
not uncommon, especially among the of the 

mimetic forms. Papilio lyrithou* for ban no 

less than six distinct forms of female, whieh 
chiefly in the extent and arrangement of the 
markings on the winp, on form 
Several of these forms may in a 

locaEty, and may resemble aa 
of Poison-eatem Thus the 
white on both winp, rnrik f with on the 

wing only, and pompmim without any al) fly 

together in Edo Grand do Sul and 
the three distinct Pharmaoophagua 
chamaeonia, and (PL XIII). It li 

of note that mimics ore provided by 




NEW-WORLD MIMICS 45 

groups of Swallow-tails in S, America, whereas in 
Asia the Cosmodesmus division never provides mimics 
for Pharmacophagus models (of. Appendix II). 

In the second and smaller group of the Pharma- 
cophagus Swallow-tails the general colour scheme is a 
more or less dark metallic blue-green with a tendency 
towards the obliteration of light markings. Some 
idea of their appearance may be got from the figure of 
the Central and N. American P. philenor on PI. XVI, 
fig. 1. Though one or two unprotected PapiHos 
in S. America fall more or less into this colour scheme, 
the group, from the point of view of mimicry, is not 
nearly so important as the red-spotted one. 

Nevertheless the blue-green Pharmacophagus group 
as represented by P. philenor is supposed to play a con- 
siderable part in mimicry in N. America. P. philenor 
is found throughout the greater part of the Eastern 
United States, straggling up as far as the Canadian 
border. On the west it is also found reaching up 
to North California. Over considerable parts of its 
range are three other Swallow-tails, belonging to 
the unprotected PapiHos, which are regarded by 
Professor Poulton and others as mimics of philenor 1 , 
One of these, P. troilua, is dark brown with a dusting 
of blue scales over the hind wing (PI. XVI, fig. 2). 
The sexes here are more or less alike. Troilua stretches 
up into North-west Canada some way beyond the 
limits reached by its model. P. glaucua is a black 
and yellow Swallow-tail with two forms of female. 

1 Of. Poulton, Darwmandthe 'Origin,' 1909, pp. 177-186. 



46 



NEW-WORLD MIMICS 



[rif. 



One of these resembles the male while the other i* 

darker and is said to mimic phiknor. It w known 

as the turnus form and is found more commonly in 

the southern part of the range of the B|wcie, i>. in 

the country where philenor is more plentiful The 

third species, P. asterim, has a more aoutherly cli- 

tribution. Its female is darker and nearer to philmnr 

than the male. It must* however, be admitted 

that none of the three a vary 

resemblance to phiknor. It is that thin 

is because P. phiknor is a tropical form which hmi 

only recently invaded N. America, The of 

phiknor has, as it were, induced the mimtektitK 

Papilios to turn dark, but the mode! ha* not fawn 

long enough in contact with them for tha 

to become a close one. The explanation, tiewtnw, 

hardly accounts for the fact that the mimic 

of the three, P. troilm, in which both are 

is found far north of philemr* Either the 

was established without the influence of the Ptmritui- 

cophagus model, or eke the rapidly 

its range northwards having 

under the influence of in the aouth. 

in that case the critic may ask why it not to 

the original pattern now that it has got the 

model's sphere of influence. On the whola it 

at present quite doubtful whether any of 

a mimetic nature I*. 

these three species of Papilio. 

P. philenor is also as m 




rv] 



NEW-WORLD MIMICS 



47 



for two Nymphaline butterflies in the United States. 
One of these is the large FritiUary Argynnis diana 
of which the dark female has a markedly blue tint 
on the upper surface (PL XVI, fig. 3), The other 
is a Limenitis 1 related to our own White Admiral. 
This form, L. astyanax (PL XVI, fig. 5), is a dark form 
with a bluish iridescence on the upper surface. It is 
found, like P. philenor, over the greater part of the 
Eastern States, while to the north, near the Canadian 
boundary, its place is taken by L. arthemis with 
prominent white bar across both wings (PL XVI, fig. 4). 
There is reason for believing that where the two overlap 
there is occasional inbreeding, and that the hybrid 
is the form known as proserpina, resembling astyanax 
more than arthemis. It must be admitted that in 
general appearance L. astyanax and Argynnis diana 
are more like Papilio troilus than P. philenor. In 
explanation it has been suggested that all the mimics 
are on the way to resembling P. philenor, and con- 
sequently we should expect them at certain stages 
to shew more resemblance to one another than to 
the form they have all as it were set out to mimic. 
On this view they will aU arrive at a close resemblance 
to philenor in time. Another explanation is that 
favoured by Professor Poulton on which it is assumed 
that we are here dealing with a case of MuUerian 
Mimicry, all of the species in question being distasteful 
with the exception perhaps of A. diana. Thus troilus 
and astyanax though distasteful are less so than 

1 The N. American members of this genus are often referred to as 




NEW-WORLD MIMICS 



[en. 



philenor. Hence it is of advantage to them to- have 
even a chance of being mistaken for the more obnoxious 
philenor, and so the one has come from the black 
and yellow Swallow-tail pattern and the other from 
the white-banded arthemw form to what they are, 
i.e. more alike to one another than to philcnor. They 
now form a MiiHerian combination for mutual protection 
along with the dark females of g?auc<tM and a*teriu*. 
But they are themselves still moderately di*tAMtefui 
so that it is to the advantage of the female of Aryynni* 
ctiana to mimic them, Whether they are all on the 
way to resembling phttetior clammy, or whether 

they have sufficiently vindicated their inedihfe proper- 
ties and are now stationary, it i for th future to 
reveal to posterity. Lastly we have the view that 
these different species have attained their prtwttt 
coloration entirely independently of one another, 
and that we are not with 

at all. Since the sole evidence at 

is that based on 

distribution, the view of thin 

largely upon, personal inclination, 

Though til just are very pro- 

blematically mimetic* N. America ytt 

examples of 

forms as dose as any that in the In 

this region aa?e found two of the /town'* 

D. archippm oooumng all over the United 
and reaching up northwawii into IX 

found in the South-eastern f,f. in 

where it is said to be more 



rv] 



NEW-WORLD MIMICS 



D. archippus (PL XVI, fig. 8) is very similar to the 
oriental D. plexippus (PL IV, fig. 2), from which 
perhaps its most notable difference lies in the extent 
and arrangement of the white spots near the tip of 
the fore wing. D. Berenice is not unlike archippus in 
its general colour scheme but is smaller and darker 
(PL XVI, fig. 9). 

We have already had occasion to mention the 
common Nymphaline, Limenitis arthemis (PL XVI, 
fig. 4) which is found in Canada and the North- 
eastern States. Widely spread over N. America is 
a close ally of this species, L. archippus, which, though 
so similar in structure and habits, is very different 
in external appearance. As appears from PL XVI, 
fig. 0, L. archippus is remarkably like the Danaid 
which bears the same specific name. In the Southern 
States L. archippus is replaced by a form, slightly 
different in details of pattern and distinctly darker, 
L. floridewia (^eros) (PL XVI, fig. 7). In Florida 
occurs also the darker N. American Danaid, D, berenice, 
to which the colour of L. floridensis approximates 
more than to D. arcMppus, and it is of interest 
that although the last named is also found in this 
locality it is said to be much less abundant than 
D, "berenice. Nevertheless it appears to be true that 
the range of L. floridensis is much more extensive 
than that of its model ; in other words, that there 
are considerable regions where L. floridensis and 
D, archippus coexist, and from which L. archippus 
and D. berenice are wanting. 



p, M. 





CHAPTER V 

80M1 CRITICISM** 

THE facts related in the two cltfifrw art* 

sufficient to make it clear romarkuhio 

resemblances between belonging a* a rule 

to widely different groups eorwtitttte a jhi*nu 

menon, and as such demand an explanation* Clue 
explanation, that in terms of tho theory of mimicry, 
has already been outlined, and we may now turn to 
consider it in more detail Some ago Wallace*, 

combating the suggestion that of 

resemblance might be coincidences, down 

five conditions which ho to 

all such cases, and rendered ufeterfj 
explanation other than in of 

These five conditions are of und 

may also serve as a peg for sundry In CMIII- 

nection with the mimicry theory. They are an : 

(1) That the imitative occur in the 
area and occupy th very as the 

(2) That the imitators w 
defenceless. 

1100 (lit issft), p. 







OH - 



n 



SOME CRITICISMS 



61 



of 



- 

planation it will be oonvaS^ j nunuray ex- 
with these five condS ThL , S " Onne0tion 



only found 



Dismorphia resemblances in the 
Ithormme models are as a rule 
very abundant. Two hundred 1 



52 



SOME CRITICISMS 



[Of, 



But though mimic antl model may be found together 
in the same locality, they do not always wrc'upy the 

same station in the sense that they fly together. 
According to Seitz 1 the I>iniorp!iw the.nute.!vei cl 
not fly with the Ithomiinea whieh they mimic. Tin* 
occurrence of butterflies is largely conditioned by the 
occurrence of the plants on which the frwl*. 

and this is especially true of the femak% which, a* 
already been noticed, ii more commonly mimetic 
than the male. The female of /'apilio for 

instance, is found flying where arcs to l found the 
wild citronaceous plantH on which it* feed*. 

On the other hand, ita Ho-called mocieln, /'0/>i7iV 
and P. arifitolachiae., arc generally in the |mximity 
of the AristoloohiM on which their fwl. T!w 

two plants QXQ not always found toother, mi 
one frequently comes /*. 

is very abundant whilo the are cr 

Though in the majority of lite 

and the imitated occur in the tlitu I 

not always so. The of the 

ty/p&rbiw (PL IV, fig. 8), for 

difficult to distinguish from 
flying, although when at rest the 
the two . is sufficiently obvious. are 

plentiful in Ceylon but 
The Danmd te a low-country whik the 

is not found until fwl up* flit* two 

species affect entirely 




V] 



SOME CRITICISMS 



53 



come into contact with each other. Where on is 
plentiful the other is not found. It has been suggested 
that migratory birds may have come into play in 
such cases. The bird learns in the low country that 
Z>. plexippua is unpleasant, and when it pays a visit 
to the hills it takes this experience with it and avoids 
those females of the Fritillary which recall the un- 
pleasant Danaine. 

Migratory birds have also been appealed to in 
another case where the resembling species are even 
further removed from one another than in tho last 
case. Hypolimnas misippm is common and widely 
spread over Africa and Indo-Maiaya, and the male 
(PL IV, fig. 8) bears a simple and conspicuous 
pattern a large white spot bordered with purple 
on each of the very dark fore and hind wings. The 
same pattern occurs in the males of two other Nym- 
phalines allied to H. miaippus, viz. Athyma punctata 
and Limemtis al&omaculata. The two species, however, 
have a distribution quite distinct from that of H. 
misippm, being found in China, It has nevertheless 
been suggested by Professor Poulton 1 that the case 
may yet be one of mimicry. According to his explana- 
tion, //. misippm is unpalatable, tho well-known 
association of its female with Danais chryaippwt being 
an instance of Mtillerian mimicry. Migratory birds 
did tho rest. Having had experience of //. misippus 
in tho south, on their arrival in China they spared 
such specimens of Athyma punctate and Limenitis 

1 KMUJ/H on Evolution, IOOB, p. 381. 






! fit. 





atfoomaculaia a approached to //. 

in pattern, and no I.lir 

The explanation is Init A will 

probably commend to iwt, Othr an* 

known in which two btitterflit** i^nr it 

in pattern and yet Am widdy 

Several gpectefl of tht* 8. 

Adelpha are in colour thi* African 

poggei which an A ttiocli*! fr 

species. The little S, /-ur/W^.*iitt 

would certainly be rithor IM tt 

for or a miraki of thi* AV/ii!. nr-mri^, illii tlitj 

two ooctir together. Nrvirt.hrlri*K f 

resemblance between tititt^rllit^ tit 

parts of the world arts t** 

emphasis the that flit* of 

resemblance are found in or In 

little groups, 

(2) Thai ike aw rt* ilt/** n j * |# , 

In the of biitt*rfii **Itfwn*i* M n* rl i irtt** 
a dkagreeable flavour it*i |>^t#*r dift.t^trftil 

to birds and to wmiM*U ti%fitirT* 

Feeding tilttt* {il citiif*r IJCf 

wf Iiiitt4>tlli<^i 

the HolicKifiini'A, mut 

Phanaaoopbagia Paptlitw mtiirii 

are generally drawn- art* e)ianwt<*rt*t'fi l*y 
taste, while as a role tltia k tiot tnw for tin* 
TMe qmJtty i fwf|iit*iitly 

by a more or tan tyj* tif 



SOME CRITICISMS 



55 



though this is by no means always so. Many Euploeas 
are sombre inconspicuous forms, and it is only some 
of the Ithomiines that sport the gay colours with which 
that group is generally associated. The members of 
the distasteful groups usually present certain other 
peculiarities. Their flight is slower, they are less 
wary, their bodies are far tougher, and they are more 
tenacious of life. The slow flight is regarded as an 
adaptation for exhibiting the warning coloration to 
the best advantage, but from the point of view of 
utility it is plausible to suggest that the insect would 
be better off if in addition to its warning coloration 
it possessed also the power of swift flight 1 . It is 
possible that the peculiar slowness of flight of these 
unpalatable groups is necessitated by the peculiar 
tough but elastic integument which may present an 
insufficiently firm and resistant skeletal basis for 
sharp powerful muscular contraction, and so render 
swift flight impossible. It is stated that the flight 
of the mimics is like that of the model, and in 
some cases this is undoubtedly true. But in a great 
many cases it certainly does not hold good, PapiUo 
dytia (PL I, figs. 7 and 8) is a strong swift flyer 
very unlike the Danaine and Euploeine which it is 
supposed to mimic. The flight of the female of 
Hypolimnas misippm (PL IV, fig. 7) is quite distinct 
from that of Danaia chrysipp^, while the mimetic 

1 Thoao "unpalatable" butterflies are sometimes extensively 
preyed upon by insectivorous birde, when they fall an easier prey owing 
to their slowness (of. p. 112). 




[rn, 

forms of P. fly Hfc* ** tron-mwiHir 4*1*1*. a 

mode of flight so different from thnt of th* tm 

that there" is no difficulty in 

many yards away. Hwift ** rM-Kmd 

as one of the chief mode* of lifrii lit a 

and on this score the mimic? in off 

the model. And of it ut lw 

that where the mode of w tti< prifftivc 

value of the t* very 

(3) jptel lAe turf \** 

in twdKwfewfa* 

In the majority of thin i* '*rtJiiitly trtit*. 

Probably all the Old- World 
Danalnw are frr<|iitt!y viry 

soaroer, than their Tttk I I'viili'itt 

a study of the more oomptvherwiv* 
of Lepidoptera. The tnirnlc* in 

expensive than Uits not 

it costs as many poundu an tli 
But the rale in not umvemaL in 

much more common of tin Tltt* 

remarkable /I, 

(PL XI, fig. 10) as & far tin* 

phagos Swallow-tail which tl*y tutmuv Or tht* 

Ohaloorfd moth iiiir^iil*^ 1 i^ n 

abundant thi i*nrii4t />/*i 

catho/ra whloh it itwernliliM. 

It has tti 

1 8e SWtofd* Aw J^, 1HI3 |. tin, 4 
of both apeddg i 



SOME CRITICISMS 



57 



of the greater abundance of the mimic that in such 
cases we are concerned with Mullerian mimicry, that 
since both of the species concerned are distasteful 
there is not, strictly speaking, either a mimic or a 
model, and consequently the relative proportions have 
not the significance that they possess where the 
mimicry is of the simple Batesian type. It is, however, 
very doubtful whether such an explanation is of any 
value, for, as will appear later, there are grave objections 
to accepting the current theory as to the way in which 
a resemblance' is established on Mullerian lines (cf. 
pp. 72-74). 

(4) That the imitators differ from the bulk of their 
allies. 

What importance we attach to this condition 
must depend upon our interpretation of the word 
"allies" whether, for example, we use it for a small 
group of closely connected species, for a genus, for 
a group of genera, or in an even wider sense. Perhaps 
an example wiU serve to make the difficulty more 
clear. As already noticed, the S. American genus 
Dismorphia belongs to the family of Pieridae or 
"whites." Also certain species of Dismorphia bear a 
close resemblance to certain species of Ithomiinos, 
a noteworthy example being D. praxinoe and Mecha- 
nitis saturata (PL X, figs. 3 and 7), in which the 
pattern, colour, and shape of the two species are 
all far removed from what is usually understood by 
a "white." It must not be forgotten, however, that 
these matters are generally discussed by European 




SOME f'lUTK'ISMS |rn. 

naturalists who have grown up in a rrginn \vhrrr 
the majority of the "whiten" arr won* nr lr** \vhit*. 
For this reason the HtntiMiii-nt that tl jtrturiw Utf<rH 
from the bulk of iin allii'H in HKrly to iwH with 
general acceptances rsjM'cially its **mw f fit*- Njn-rii'* 
of the genus itolf (e.g., A. rrr/wi, II. X, %, I) 
are regular whit<*H in npjKarawi*. But wlm-u up 
come to look at tin* gcMtUK ?>i#wnrjthin nn a \vhli- th*' 
matter aHHumeH another contplrxioii* St-ity, ! rrr^uisr.M 
75 apecies of which about it dtmvn nrv prpfiumiimntly 
white. The reat prewnt a wou<Irrful ilivrrHtty f 
colour and pattern. BInck pnHlouiinutrK n tin- fun* 
wings, and the inwet in frwjurntly tarki*l \\iih iiy 
patches of yellow, bright, brown. wiirlH* nr biu. 
Forms which from their colour nr< Hwirly it tntiiitcM 
present neverthelena the g<*n(*rti) pattern HIP! nhajH* 
of other forms which bear a Htrong n*i*i*itibliiii-'j* t 
some Ithomime. Hometiinw a change* ttf rolmtr in 
certain patchen from blue or yi'llcnv to bright hrmvn 
would make all the diflc*rt*ntH % i*iw*{*u ti ntiii-iuiitativt* 
and an imitative HpecicH. Mon.*civi*r. flit* ticii-iiuitJttivf 
forms frequently have the ix*cmitar narrw \viiig, wi 
unusual in a Piorine, which enhantH*M tin* nm'wb!ann 
of the mimicking Hi>c(sic8 to the* !th<imitnt* intIrJ 
and which to some extent occur* (*vc*n in /). erf farm t 
Clearly we are not justified, in nay ing that. M pmrinw 
differs from the bulk of itn allk* f for iiwitlr flit* gi*tiUM 
there are many non-imitative H{XWWH whirh tiiltor 



1 Macrol&pidopt&ra o/ 
Plates 28-30. 



World, Fauna 



pp. WH-IW4, 



v] SOME CRITICISMS 59 

from it in some particulars and are alike it in others. 
There is a distinct family resemblance among the bulk 
of the Dismorphias, including practically all the mimetic 
forms, and on the whole the resemblances between 
the imitative and the non-imitative forms are as 
noteworthy as the differences. Though not exhibited 
in BO striking a fashion, the same is to a largo extent 
true of a large proportion of the eases of mimicry. 
It is on the whole unusual to find cases where a single 
species departs widely from the pattern scheme of 
the other members of the genus and at the same time 
resembles an unrelated species. Two of the best 
instances are perhaps those of Limenitis archippm 
(p. 49) arid of the Pierid Parewnia (p. 28). Of 
the total number of mimicry instances a high propor- 
tion is supplied by relatively few groups. In each 
region several main series of models and mimics run 
as it were parallel to one another. In Asia, for example, 
we have the Papiiio-Danaine series where the colour- 
patterns of a series of Danaines, all nearly related, 
are closely paralleled by those of a section of the 
genus Papilio, and by those of the Satyrid genus 
jElymnias. In Africa there is a similar Papilio-Danaino 
series though of less extent. Africa has a group of 
models not found in Asia, and the Papiiio-Danaine 
series is as it were curtailed by the Papilio-Planoma 
Borics with which to some extent runs parallel the genus 
PMudacmaa. These phenomena of parallel series have 
been mentioned here as shewing that mimicry tends 
to run in certain groups and that in many cases at 



62 



"MIMICRY 



r c:n. 



mutation, and that natural aelcction in 

merely for its survival and the elimination of tin* !e*H 

favoured form from which it aprang. 

There is a serious difficulty in the way of accepting 
the former of these two views. If our two 
model and would-be mimic are, to with, 

different in pattern, how can wo tmppow that- a 
variation in the direction of the mode! on the 
of the latter would be of any value to it 1 Take for 
example a well-known South caat* - the 



Jk 

resemblance between the yellow* btadk, brown 



Ithomiine, Mechanitis (PL X, fig. 7) initi 

the Pierine s Diamorphia (1*1, X, fi 

The latter belongs to the family of the ** whitw, 

entomologists consider that in all iu 

ancestral garb was white with a little tint 

closely allied D. (PL X, fig. 1)* 

we suppose that in such a a 

of brown and blitek on the would IM* 

to recall the Ithomiine NO bo of to tlio 

Dismorphia which it! a 

slight approach to the IthomUne i* 

by ^be males of South "white*" 

betongijig to the genus {PL X, %K, 4 itittl f*), 

But ttte colour is to the u.ttdi*r^tirfiM*0 mid 

the butterflies it b 

with a M&^aniiis wliiti* 

wMch entirely lack a of colour. If 

regarded whit as it ii to 

suppose that tikey would, be in tbeir 



VI] 



MIMICRY RINGS 



63 



by a trifling patch of colour while the main ground 
of the insect was still white. But unless they avoided 
those with the small colour patch there would be an 
end of natural selection in so far as the patch was 
concerned, and it would have no opportunity of 
developing further through the operation of that 
factor. This is the difficulty of the initial variation 
which has been clearly recognised by most of the 
best known supporters of the theory of mimicry. 
Bates himself offered no suggestion as to the way 
in which such a form as a Pierid could be conceived 
of as beginning to resemble an Ithomiine 1 . Wallace 
supposed that the Ithomiines were to start with 
not so distinct from many of the edible forms as they 
are to-day, and that some of the Pierines inhabiting 
the same district happened to be sufficiently like some 
of the unpalatable forms to be mistaken for them 
occasionally 2 . 

The difficulty of the initial variation had also 
occurred to Darwin, and he discusses it in an interesting 
passage which is so important that we may quote 
it here in full : 

It should be observed that the process of imitation probably 
never commenced between forms widely dissimilar in colour. But 
starting with species already somewhat like each other, the closest 
resemblance, if beneficial, could readily be gained by the above 
means ; and if the imitated form was subsequently and gradually 

1 "In what way our Leptatts (=Dismorphia) originally acquired 
the general form and colour of Ithomiae I must leave undiscovered." 
Trans. Linn. Soc. vol. 23, 1862, p. 513. 

2 Darwinism, 1890, pp. 242-244. 



64 



MIMICRY RINGS 



[CIL 

I* !*! 

mfifilly 



xt<*nt, 
l 



modified through any agency, the imitating form would 
along the same track, and thuu be altered to almost any M 
that it might ultimately awrame ftn appeumixw or minuting 
unlike that of the other members of the family U> which it 
There is, however, some difficulty on thin hwul, for if i* 
to suppose in some that ancient mwnliMW Wringing f 
distinct groups, before they hiui diverged to th*ir 
accidentally resembled a member of nnthi*r ami pmfwt 
in a sufficient degw to afford nomo rfight |tf'tiiii; ibi 
given the basis for the subsequent &c|Wttoii cif the* 
resemblanioe 1 . 

Both, Darwin and Wallace riogfii*H! clr*n,riy thin 
difficulty of the initial variations, and lK>t!i 
a means of getting over It on ulitiikr linm Both 
supposed that in general colour and fwtfcwi flu* 
to which model and mimic belonged far mow? 

alike originally than they aro to-*lay. Tl*y 
in fact so much alike that oomparattveiy varia- 

tions in a favourable direction on th<* of tliti mimto 
would lead to its being confused with ttin 
model. Then as the model 
conspicuously coloured, as it developed a 
more striking pattern warning would-ij of 

its unpleasant taste, the mimic 
with it through the operation of 
in the shape of the discriminating enemy, 
those most unlike the model The mimic 
in the wake of the model, as it by 

selection, til at last it was far in 

appearance from the great majority of its 

* Origin of 8ymim, 8tb Edition, IStI* p, W4 




YI] 



"MIMICRY KINGS" 



06 



In this way was offered a comparatively simple 
method of getting over the difficulty of applying 
the principle of natural selection to the initial varia- 
tions in a mimetic approach on the part of one species 
to another. But it did not escape Darwin's penetra- 
tion that such an argument would not always be 
easy of application that there might be cases where 
a given model was mimicked by members of several 
groups of widely differing ancestral pattern, and that 
in these cases it would be difficult to conceive of 
members of each of the several groups shewing simul- 
taneous variations which would render them liable to be 
mistaken for the protected model. The difficulty may 
perhaps be best illustrated if we consider a definite case. 

It is a feature of mimetic resemblances among 
butterflies that a given species in a given locality 
may serve as a model for several other species belonging 
to unrelated groups. Generally such mimics belong 
to presumably palatable species, but other presumably 
unpalatable species may also exhibit a similar colora- 
tion and pattern. In this way is formed a combine 
to which the term "mimicry ring" has sometimes 
been applied. An excellent example of such a mimicry 
ring is afforded by certain species of butterflies in 
Ceylon, and is illustrated on Plate IV. It is made 
up in the first place of two species belonging to the 
presumably distasteful Danaine group, viz. Danais 
chrysippus and D, plexippus. The latter is a rather 
darker insect but presents an unmistakable general 
likeness to D, chrysippus. Those who believe in 

p M. 5 



MIMICRY RINGS 



[CIC, 





Miillerian mimicry would regard it aa an excellent 
example of that phenomenon. For who believo 

only in Batesian mimicry D. pkxippu#t being the 
scarcer insect, must be regarded an the mimic? and 

D. chrysippus as the model In both of ftfxxiien 

the sexea are similar, whereas in the other thiw member* 
of the " ring " the female alone exhibit** the rcHemblaww. 
One of these three species is the common Nyttiphaiim*, 
Hypolimnaa misippm p of which the female an 

extraordinary likeness to D. chry*ippim when not and 
pinned out on cork in the ordinary way. The male*, 
however (PL IV, fig, 8), is an of totally 

different appearance, The upper of tho 

are velvety black with a large white 
with purple in the middle of each 1 . The "ring" In 
completed by the females of &nd 

Argynnia hyp&rUus. The former of to 

the group of Satyrine butterflies and the Is 

usually regarded as a mimic of D. 
it is not unlike in so far as the upper of tint 

wings is concerned Here the in an 

of totally dissimilar appeamnm for & 0! 

lighter brown along the outer of the hind 

the upper surface is of a uniform purple-brown 

1 H. mMppm was at one tima regftrdtod M <MUM of 
minoioiy, But in view of it* plontifulnMM, of th fiwfc tlwt II umy Im 
abundaat outside the tun fa.habibd by it* wd of tlm MA 

with wMoh it 0aa ettabliah in fawn it 

habitat, .^. 8, ^aoioft, it hw eom to be by 

of the mimicry theory M A Mtri mbnfo, Of. ' 

SvohMon, 1908, pp. S16-S17. 



" MIMICRY RINGS" 



67 



all over (PL IV, fig. 6). In Argynnia Jiyperbim 
th appearance is in general that of the Fritillary 
group to which it belongs. But in th female the 
outer portion of th fore wings exhibits much black 
pigment and is crossed by a broad whit band similar 
to that found in th same position on the wing of 

D. plexippus (PL IV, fig. 2). 

Of the five species constituting this little " mimicry 
ring " in Ceylon two, on the current theory of mimicry, 
are to be regarded as definitely unpalatable, on 
(H. misippus) as doubtfully so, while th Satyrin 
and th Fritillary are evidently examples of simple 
or Batesian mimicry. 

Now such examples as this of simultaneous mimicry 
in several species are of peculiar interest for us when 
we com to inquire more closely into th process 
by which the resemblances can b supposed to have 
been brought about. Take for example th oas of 

E. un&ularis. The male is evidently an unprotected 
insect in so far as mimicry is concerned, whU th 
female exhibits the general pattern and coloration 
characteristic of th warningly coloured and pre- 
sumably distasteful species D. plexippus or D. chrysip* 
pus. If w are to suppose this to have been brought 
about by th operation of natural selection it is clear 
that we must regard th colour and pattern of th 
male as th original colour and pattern of both sexes. 
For natural selection cannot b supposed to have 
operated in causing th male to pass from a protected 
to an unprotected condition, or even in causing him 

52 



"MIMICRY RINGS 




[ni. 



to change one unprotected condition for another. 
Probably all adherents of the mimicry theory would 

be agreed in regarding the male of 

as shewing the ancestral coloration of the ICCHH. and 

in looking upon the female as having been modified to 

her own advantage in the direction of t). pfajrippu*. 

The question that we have to try to decide in how 

this has come aboutwhether by the accumulation 

of slight variations, or whether by a midden change 

or mutation in the pattern and colour of the female 

by which she cam to UK* Danaim*. 

It is clear that if D. wmv what it w to-day 

before the mimetic approach on the jmrt of K* 

began, small variations in the would IIAW 

of no service to it, The difference between the two 

species would have been far too for individual* 

exhibiting slight variation in the of Ih 

plexippu8 to stand any of 

with this species, And 

possible natural selection ould not in, 

however, an immediate way out of the 

We may suppose that the of ttiti 

of the mimic, B. undulana 9 w not only the 

colour of its own but of the II. 



pkxippw on this supposition 
of which both then to the 

male is to-day. The in, MI 

spicuous one, and it can ba that it 

be to the advantage of D. to don a 

garb for the adve^Msement of ite 



vi] "MIMICRY RINGS" 69 

Variations in the direction of a more conspicuous 
pattern would for that reason tend to be preserved 
by natural selection, until eventually was evolved 
through its means the well-marked pattern so charac- 
teristic of the model to-day. If in the meantime 
variations in the same direction occurred among the 
females of E. undularis these would tend to be preserved 
through their resemblance to the developing warning 
pattern of the distasteful Danaine model. The develop- 
ment of model and mimic would proceed pan passu, 
but if the sexes of the mimic differ, as in this case, 
we must suppose the starting-point to have been the 
condition exhibited by the male of the mimicking 
species. 

But Argynnis hyperbius is also a species in which 
the female mimics D. plexippus ; and by using the 
same argument as that just detailed for Elymnias 
undularis we can shew that the Danaine model, D. 
plexippus, must also have been like the male of Argynnis 
hyperbius. And if the resemblance of A. hyperbius 
was developed subsequently to that of E. undulari8) 
then both D. plexippus and E. undularis must at one 
time have been like the male of A. hyperbius, a pro- 
position to which few entomologists are likely to assent. 
Further, since the female of H, misippus also comes 
into the plexippus-chrysippus combine we must suppose 
that these species must at some time or another have 
passed through a pattern stage like that of the misippus 
male. 

It is scarcely necessary to pursue this argument 



fC'IL 



further, for even the most devoted adherenta of 
theory of mimicry as brought about by the? o{terittion 
of natural selection on rnnail variations are hardly 
likely to subscribe to the phylogenetic conaequeneea 
which it must entail in where a model in inimieked 

by the females of several whom? are 

widely dissimilar in appearance. 

Even if w suppose the two Danaine* to have 
been originally like the male of one of the three mimir*, 
we must still suppose that the femalen of tin* cither 
two originated as "aporte, 1 * Huffieiently near to Itittiftinwt 
to be confused with thorn* But if emit 

be produced suddenly by Home mutatinim) 
not at present understood, why ahould not 
sports be the females of the three mimicking 
as we see them at present I Why ntxti wi* 
that there were intermediate Ilia 

mimicking female and the original hy|x>thettcikl 
which was like the male ? If a whieh 

was sufficiently similar to an un]>alatabb to 

be confused with it, it w 
that, although relatively to with, it 

rapidly at the of the 

male-Ik female until the waa tIItniitL We 

shall, however, return in a (> IKI| to 

the argumsat by which this can be 

So far we have we tin* 

extreme views as to the way in whieh 
resemblance may be to Of 

the two that which the to 



VI] 



MIMICRY RINGS" 



71 



been brought about by a succession of slight vari- 
ations must also assume that model and mimic were 
closely alike to start with, and this certainly cannot 
be true in many cases. On the other hand, there is 
so far no reason against the idea of supposing the 
resemblance to have originated suddenly except what 
to most minds will probably appear its inherent im- 
probability. 

There are writers on these questions of mimicry 
who adopt a view more or less intermediate between 
those just discussed. They regard the resemblance as 
having arisen in the first place as a sport of some 
magnitude on the part of the mimic, rendering it 
sufficiently like the model to cause some confusion 
between the two. A rough-hewn resemblance is first 
brought about by a process of mutation. Natural 
selection is in this way given something to work on, 
and forthwith proceeds to polish up the resemblance 
until it becomes exceedingly close. Natural selection 
does not originate the likeness, but, as soon as a rough 
one has made its appearance, it comes into operation 
and works it up through intermediate stages into the 
finished portrait. It still plays some part in the 
formation of a mimetic resemblance though its role is 
now restricted to the putting on of the finishing touches. 
Those who take this view hold also that the continued 
action of natural selection is necessary in order to keep 
the likeness up to the mark. They suppose that if 
selection ceases the likeness gradually deteriorates 
owing to the coming into operation of a mysterious 



72 



"MIMICRY RINGS" 



if 



process called regression. This idea involve* certain 
conceptions aa to the nature of variation which w* 
shall discuss later. 

Though it is difficult to mimicry 

as produced by the accumulation of wimll 
through natural selection, it w jjerhapH rather more 
( plausible to suppose that a Impfwn 

ia connection with the numerouft irwt-apis of MiUlcrron 
mimicry. For sino the end In throivticAlly to 

the advantage of both of hut ni% it 

is possible to argue that the would l mm 

pLLfied by their meeting on another halfway, it* 
himself originally suggested. Variiitiniw on thi 
of each in the direction of the other would be favourably 
selected, the mimicry being reciprocal 

Difficulties, however, begin to whem w inquire 
.into the way in which this unification of 
be conceived of as having about. Iff iso 

have these difficulties more forcibly 

than by Marshall 8 in aa able 

years ago, and perhaps the of 

them is to take a hypothetical by an 

an illustration, 

Let us suppose that in the ih*ts two equally 

distasteful A and B, with ti 

though distinct warning pattern, and 
1000 individuals yearly to the of 



of MOItaft it ty 



1 An English 
Proo. J9n, 5oo., 1878, p. 
' 



YI] 



MIMICRY RINGS" 



73 



birds. Further let it be supposed that A is a common 
species of which there are 100,000 individuals in the 
given area, while B is much rarer, and is represented by 
6000. The toll exacted by young birds falls relatively 
more lightly upon A than upon B, for A loses only 
1 %, whereas $'s loss is 20 %, Clearly if some members 
of B varied so that they could be mistaken for A it 
would be greatly to their advantage, since they would 
pass from a population in which the destruction by 
young birds was 20 % to one in which it would now be 
rather less than 1 %. Moreover, as the proportion of 
B resembling A gradually increased owing to this advan- 
tage, the losses suffered by those exhibiting the original 
B pattern would be relatively heavier and heavier until 
the form was ultimately eliminated. In other words, 
it is theoretically conceivable that of two distasteful 
species with different patterns the rarer could be 
brought to resemble the more abundant. 

We may consider now what would happen in the 
converse case in which the more numerous species 
exhibited a variation owing to which it was confused 
with the rarer. Suppose that of the 100,000 individuals 
of A 10,000 shewed a variation which led to their being 
mistaken for B, so that there are 90,000 of th A 
pattern and 15,000 of the B pattern of which 10,000 
belong to species A. A will now lose 1000 out of the 
90,000 having the A pattern, and f xlOOO out of the 
10,000 of species A which exhibit the B pattern. The 
toll of the birds will be ^ of those keeping the original 
A pattern, and -^ of those of species A which have 



'MIMICRY 



[on. vi 



i 



assumed the B pattern. The mortality among Ilia 
mimetic members of A is six timea an an among 

those which retain the typo form, It b clear therefore 
that a variation of A which can bo mistaken for ft in 
at a great disadvantage m com parcel with tho typo 
form 1 , and consequently It must be HUpfxHtec) that. tht> 
Mullerian factor, as the destruction chic* to export- 
mental tasting by young birds ia tinned, cannot bring 
about a resemblance on the part of a morr mmiprmi* 
to a leas numerous species, FurtJier, an 
on to shew, there can bo no approach of one- HJIWM* to 
the other when the numbers are approximately wjual. 
A condition essential for the of ti mimetic 

resemblance on Mtlllerian lines, no lens on 

sian, is that the less numerous on 

the pattern of the more numerous. Consequently the 
argument brought forward in this part of 

chapter against the establishing of a by 

a long seriee of slight variation! is equally valid for 
MUllerian mimicry 8 . 

1 Provided of oouwe that the type form In tl 

If tha variation oeourred aimultaatKiuiily i more fit* % f A the 

advantage would aatumlly l with the vnriatton. 

a It i possible to Imagine no thmtgh 

that tt would ooow, Bup|xe for ttXAinpta 

of diitMtrfal my SO, all of i 

that in all of ttarn ft pftrtitnilar viiUmi ; 

then il th total thtwlng that variation from tltt ft) 

gceatesc thaa the wmbw of ny on of the JJ 4 tip* Stft 

would com to ialm on the form of tto new In iltfa wy it- fa 

imaginable timt tito new pattern would all th* obi 




CHAPTER VII 

THE CASK OF PAPILIO POLYTMB 

MANY instances of mimicry are known to-day, but 
comparatively few of them have been studied in any 
detail. Yet a single carefully analysed case is worth 
dtozens which are merely superficially recorded. In 
trying to arrive at some conception of the way in which 
the resemblance has come about we want to know the 
nature and extent of the likeness in the living as well 
as in the dead; the relative abundance of model and 
mimic ; what are likely enemies and whether they could 
be supposed to select in the way required, whether the 
model is distasteful to them; whether intermediate 
forms occur among the mimics ; how the various forms 
behave when bred together, etc., etc. Probably the 
form that from these many points of view has, up to 
the present, been studied with most care is that of the 
Swallow-tail, Papilio polytea. It is a common butterfly 
throughout the greater part of India and Ceylon, and 
closely allied forms, probably to be reckoned in the 
same species, reach eastwards through China as far as 
Hongkong. P. polytes is one of those species which 
exhibit polymorphism in the female sex. Three dis- 
tinct forms of female are known, of which one is like the 
male, while the other two are very different. Indeed 





THE CASE Of PA PI 110 POLYTRS [en. 

for many years they wore regarded am diittinct 

and given definite specific name*. To Wallace 

the credit of showing that threw of 

are all to be regarded an wivea of tho tyjH* of 

male 1 . Ho shewed that thoro were no crorro- 

sponding to two of the females; alo that tin* 

male form was always to be found wherever any of the 

females occurred. As the of breeding *x|K*ri* 

merits in more roeent Wallace Vi fonHttMion* 

been shewn to be perfectly round. 

The male of jwtyf^ (PL V, fig. I) in a hamlm*nu* 
blackish insect with a wing of ftlwnil four 

inches. With the exception of yf*Howt#h*whit 

spots along their outer margin the fort* are entirely 

dark, Similar spots occur along the of th hind 

wing also, while the middle rtitw a of nix 

yellowish-white patehew producing the of 

a broad light band. The and abdomen are fall 

black, though the black of the in relieved by a few 
lighter yellowish The under IK 

like the tipper, the chief a of 

small and slightly reddish running tha 

light band aear the of the hind (!I. V, 

fig. la), In som specimen* are 

absent Oae form of | like 

the mal (PL V, fig, 2), the one 
that the lunulee on the under of the 

are generally a trifle For *h* 

be called the M form. Hie of 

, Lfon. jfee, vet, ft 



vn] THE CASE OF PAPIL10 POLJTES 77 

differs in many respects from the male and the M 
female. Instead of being quite dark, the fore wings are 
marked by darker ribbed lines on a lighter ground 1 
(PL V, fig. 3). The hind wings shew several marked 
differences from those of the male. Of the series of 
six patches forming the cross band the outermost 
has nearly disappeared, and the innermost has become 
smaller and reddish. The middle four, on the other 
hand, have become deeper, reaching up towards the 
insertion of the wing, and are pure white. A series 
of red lunules occurs on the upper surface outside the 
white band, and the yellowish-white marginal markings 
tend to become red. These differences are equally 
well marked on the under surface (PL V, fig. 3 a). 
The colour of the body, however, remains as in the 
male. From the resemblance shewn by this form to 
another species of Swallow-tail, Papilio aristolochiae 
(PL V, fig. 5), we shall speak of it as the A form. 

The third form of female is again very distinct 
from the other two. The fore wings are dark but are 
broken by an irregular white band running across the 
middle (PL V, fig. 4), and there is also an irregular 
white patch nearer the tips of the wing. The hind 
wings, on the other hand, are characterised by having 
only red markings, The yellowish-white band of the 
male is much reduced and is entirely red, while the red 
lunules are much larger than in the A form. The under 
surface (PL V, fig. 4 a) corresponds closely with the 

1 These darker ribs are also present in the male and M female but 
are obscured owing to the generally deeper colour. 




78 THE CASE OF PAPILIO frit. 

upper* The body remains black a* in all the other 
forms. This type of female a to 

Papilio hector (PI. V* fig. 6), and for we 

shall speak of it as the // form. It nhoId bo itddrti 
that those three forms of are quit* indintinguinh* 

able in the larval and 

It Wallace who cifferwl an of 

this interesting in of mimicry. According 

to this interpretation P, ii a form, 

The larva, which on and tin* 

chrysalis are both in thwr 

surroundings, They may be m frotortiv<*ly 

coloured, and consequently to 

secution. The original coloration ii of tin* 
and the M female. From tlm other two of 

female have diverged in the direction of 
of less oonspiouousneaa, although the 
bility of the inae-ot might led u* to a 

less conspicuous coloration would to 

its advantage. But two the 

two species Papilio and 

which, though placed in the M F 

belong to a very of it 1 . The 

of these two are 

and red with spiay They feed the 

poisonous Pur 

also from the foot that the 
both conspicuous and plentiful It to tlmfc 

are unpalatable* la abort, they ace the 



VH] THE CASE OF PAPILIO POLJTE8 79 

which the two polytes females that are unlike the male 
have been built up by natural selection. 

The suggestion of mimicry in this case is supported 
by the fact that there is a general correspondence 
between the areas of distribution of model and mimic, 
P. hector is not found outside India and Ceylon, and 
the H female of P. polytes is also confined to this area, 
P. aristolochiae, on the other hand, has a much wider 
range, almost as wide indeed as that of P. poll/tea 
itself. Generally speaking the A female accompanies 
P. aristolochiae wherever the latter species is found* 
Beyond the range of P. aristolochiae, in northern China, 
the M female alone is said to occur. On the other 
hand, as the matter comes to be more closely studied 
exceptions are beginning to turn up. The H female, 
for instance, is found on the lower slopes of the Hima- 
layas, far north of the range of P, hector, and there 
are indications that a careful study of the distribution 
in China and Japan may prove of importance. 

Moreover, the investigation of a smaller area may 
also bring to light points of difficulty. In Ceylon, for 
example, P. polytes is common up to several thousand 
feet, while P. hector is rare at half the height to which 
polytes ascends. Nevertheless the H form of female is 
relatively just as abundant up-country where hector 
is rarely found as it is low down where hector is plenti- 
ful 1 . On the other hand, P, aristolochiae may be exceed- 
ingly abundant at altitudes where hector is scarce. Yet 
the A form of polytes is no more relatively abundant 

1 SpoHa Zeylanica, 1910, 



PI 



80 THE CASE OF PAP1LW [at* 

here than elsewhere on the island. All over Ceylon, 
in fact, the relative proportions of the thrw forms of 
female appear to be the same, quite irrespective of the 
abundance or scarcity of either of the nuxic*ift. An, 
however, we shall have to return to thin paint later, 
we may leave it for the moment to conmder other 
features of this of P. polflw, 

In collections of insects from India or (Vylon it in 
not unusual to find of the /I form of fetnala 

of polytea placed with P. the. // form 

with P, hector. When the arts old and faded 

and pinned out on cork the in a very natural 

one. But after all the enemies of do not hunt 

it in corked cabinets, and any estimation of 
to be of use to us must be upon the living 

Are the resemblances of the mimics to tit when 

alive so close that they might be to deceive 

such enemies 1 as prey upon them and no difHoulty 
in distingtdshing the form of from. f\ 

tolochiae or P. hector 1 

To answer for a bird is a 
We know so little of the 
whether of or But on 

irom the speoialimtion of It 

is probable that the of I keen, 

whether- the colour ii the an our 'is 

doubtful 2 . On the other hand, the 

it lor the that, tt of of 



1 W@ 
iniinicry, 

Be later, p, 110, 



of (f, limp, IX). 



vn] THE CASE OF PAPILIO POLJTS8 81 

Is relatively poorly developed in birds, and from this 
we can only argue that the senses of smeU and taste 
are not especially acute. KeaHy we can do Httle more 
than to describe how these mimetic resemblances 
appear to our own senses, and to infer that they do not 
appear very different to the bird. If there is any 
difference in keenness of perception we shall probably 
not be far wrong in presuming that the advantage 
rests with the bird. After all if there is any truth in 
the theory of mimicry the bird has to depend largely 
upon its keenness of sight in making its living, at 
any rate if that living is to be a palatable one. If 
natural selection can bring about these close resem- 
blances among butterflies it must certainly be supposed 
to be capable of bringing the bird's powers of vision to 
a high pitch of excellence. 

Returning now to the case of P. polytes, there is 
not the least doubt that to the ordinary man accustomed 
to use his eyes the A form of female is easily distinguish- 
able from P. a/riatolochiae, as also is the H form from 
P. "hector. The two models have a feature in common 
in which they both differ from their respective mimics. 
In both of them the body and head are largely of a 
brilliant scarlet, whereas neither of the mimics has a 
touch of red on the body. In the living insect when 
the body is swelled by its natural juices the effect is 
very striking 1 . It gives at once a "dangerous" look 

1 The specimens figured on PI. V were dried in papers when, taken. 
The body is consequently muoh compressed and the characteristic 
scarlet of P. hector and P. ariatolochiae is largely hidden. 

p. M. 6 



1.1 



82 THE OF PAHLIO [cm. 

to the insect when net t Jed, even nt a of 

yards, and this although one be perfectly 
with its harm lew nature* The on the cither 

hand with their aombre-coloured never 

otherwise thari the inoffemiive they 

The "dangerous" look due to the of 

the body and of in v 

Inforced by the quality of the red on the of 

the winga In both it w a 

red suggestive of a powerful dye, 

CBR^? *^' 

red as occurs in the mimic* i* a totally 

distinct oolour. The in t* even 

marked, on the under on the ujpr ( 1*1, V , 

figg, 3 a), and the not in 

with winga either or w tin 

bility of an ordinarily 

for model in either at a of 

yards* 

It may, however, b it in not at 

rest but during flight the 

protects the inimio from tiitJt can 

hardly be trae t for the of one 

of the and 

Bdmfa. P. and K fly much In the 

same wfty, They one the of 

mainly with fore 

so that the of the not 

on the whole and Tbe of all the 

different forms of i and quite 

feom that of the It in a but 



vn] THE CASE QE PAPILIO POLJTES 83 

heavy and lumbering up-and-down flight. One gets 
the impression that all the wing surface is being used 
instead of principally the fore wings as appears in 
P. hector and P. cvristolocMae. The difference is difficult 
to put into words, but owing to these peculiarities of 
flight the eye has no difficulty in distinguishing between 
model and mimic even at a distance of 40 to 50 yards. 
Moreover, colour need not enter into the matter at alL 
It is even easier to distinguish model from mimic when 
flying against a bright background, as for instance when 
the insect is between the observer and a sunlit sky, 
than it is to do so by reflected light. I have myself 
spent many days in doing little else but chasing $>olytes 
at Trineomalee where it was flying in company with 
P. hector, but I was never once lured into chasing the 
model in mistake for the mimic. My experience was 
that whether at rest or flying the species are perfectly 
distinct, and I find it difficult to imagine that a bird 
whose living depended in part upon its ability to dis- 
criminate between the different forms would be likely 
to be misled. Certainly it would not be if its powers 
of discrimination were equal to those of an ordinary 
civilised man. If the bird were unable to distinguish 
between say the A form of female and P. aristolochiae 
I think that it would be still less likely to distinguish 
between the same A form and the male or the M form 
of female. Eor my experience was that at a little 
distance one could easily confuse the A form of 
polytes with the male. Except when one was quite 
close the red on the A form was apt to be lost, the 

62 



84: THE CASE OF PAP1L10 [en. 

white markings on the hind wing were readily confnued 
with those of the male, and one had to depend entirely 
on the lighter fore wing, Unkss the bird were keener 
sighted than the man the A form would be man* likely 
to be taken in mistake for it* unprot^Uxl relative than 
avoided for its resemblance to the prenumiibty un- 
palatable model On the other hand, if the bird were 
sufficiently keen sighted never to eonf tine the A 
with the male form it* would be too keen to be 

&*s 

imposed upon by inch a* }tef,w*n 

the A female and ,P, 

Those, however, are not the only rriiiciumfi of Ilia 
theory of mimicry which the utticly of thin 
upon us. Papilio jmlytea Is ones of the few mimetic 
species that has been bred, and in no other of 

polymorphism is the relation between thu different 
forms so clearly understood. For wa am 

indebted mainly to the careful of Mr J. (X F. 

Fryer, who recently devoted the of two 

to breeding the of thin in 

Ceylon 1 , Fryer to the an ex- 

planation of this curious ig on 

MendeEan lines. At first tjin 

appear complicated, for any ona of the of 

female can behave in For the 

sake of simplicity we may for the 
the A and E as the the 




vn] THE CASE OF PAPILIO POLYTES 85 

The different kinds of families which, each of the three 
females can produce may be tabulated as follows : 

(a) The M form may give either: 

(1) M only. 

(2) M and mimetics in about equal numbers. 

(3) Mimetics only. 

(/3) The A form may give either: 

(1) M and mimetics in about equal numbers. 

(2) M and mimetics in the ratio of about 1 : 3. 

(3) Mimetics only. 

(y) The H form may give either: 

(1) M and mimetics in about equal numbers. 

(2) M and mimetics in the ratio of about 1 : 3. 

(3) Mimetics only. 

The males are in all cases alike to look at but it must 
nevertheless be supposed that they differ in their 
transmitting powers. In fact the evidence all points 
to there being three different kinds of male correspond- 
ing to the three different kinds of female. But they 
cannot shew any difference outwardly because there 
is always present in the male a factor which inhibits 
the production of the mimetic pattern even though the 
factor for that pattern be present. 

Returning now to the records of the females it 
will be noticed that although the M form may breed 
true the mimetics never give the M form alone. Where 
they give the M form among their progeny they produce 
mimetics and non-mimetics either in the ratio 1 : 1 
or of 3 : 1. This at once suggests that the non- 




86 THE CASE OF PAPILIO [rn. 

mimetic is recessive to the mimetic form*- that the 
immeties contain a factor which doen not oeettr in the 
non-mimetics. If this factor, which may he enilcd A% 
be added to the constitution of a non-mimetie female. 
it turns it into a mimetic. If A' be added to n tunic* 
such an individual, though incajiahle of itnelf exhibit ing 
the mimetic pattern owing to the inhibitory factor 
always present in that beennieH cnimhle of tntim* 
mitting the mimetic factor to it oflnpring. 
in the usual Mendeiian way the formulae for 
different butterflies are ii foliown: 



i a xx 



/ 
H XX 

If Xx 



ill 
f2i 

-at 



where X stands for the mimetic factor and / for tins 
factor which inhibits the action of X. All are 

heterozygous for / but during the of 

characters at some in the of the 

families only the male-producing conic* to 

the factor 1, It is lacking in all the 
sperms formed by the -male, 

<j (1) not contain the for the 

conditioE and only of the Jf form 

mated with an Jf 9. <? (2) on the I homo- 

ssygouB for the factor Jf, and all of hi 

germ eels oontsdn it This it the 
nothing but mimetic with form 01 

female he is bred, a (8) is for X ; 

to say, one half of hia oelk It f the 

haH not Witi the Jtf9 he give 



VH] THE CASE OF PAPILIO POLJTES 

of offspring with and without X, i.e. half of his daughters 
will be mimetic and the other half non-mimetic. With 
a heterozygous mimetic female (uXx), which is also 
producing germ cells with 'and without X in equal 
numbers, he may be expected to give the usual result, 
viz. dominants and recessives in the ratio 3:1; or 
in other words mimetic and non-mimetic females in 
the ratio 3:1. 

One of Fryer's experiments may be given here in 
illustration of the nature of the evidence upon which 
the above hypothesis depends. 



H $ (wild) 



H?(wild) 



x 



12 BJ 




\ 

XH? 



i I 

10 H$? 2 



Families were reared from the two wild H females 
of whom nothing was known either as to ancestry or 
husband. The first family contained 10 M and 7 H 
females. Hence the original wild mother was probably 
UXx and had mated with a male of the constitution 



THE CASE OF PAPILIO POLYTKS [CH. 

Iix%. The family from the wild // female con- 

tained 28 // and 7 II fomafoa; i>. the In which 

these two forma appeared not fur from 3:1. 

Hence the wild female probably nXx tier 

husband liXx* If this were o no mo of thr 26 <M 
should receive the JT factor from both jMirtnif* mud 
consequently be JtXJf in conntttution. Thi* 
almost certainly so in the of flics in 

this brood by with an M ffitiali* from 

the other brood. All of his 12 wort* of the 

H form, as should have the litwi hfo Con- 

stitution been HXX. Bupporanx thin t IH o, all hi* 
offspring, of both rauat bo for JC, 

Consequently any pair mated to^thrr ttlnnilil 
both H and M femakw In the of thm* of tlia 

former to on of the latter. In Mr Fryer* j* exfK*rimt*nt 
two malea and two at 

mated together. In the one nix /I and nc^ if 

female were produced, in the ten H and two M 

females. As was eiproted both of 

appeared, and the looked-for of I/ to otic Jf 

was, in view of the of the not 

departed from widely in 

In the M &n ttlttmtirt f the 

mimetic happen to be all of the If form. In 

other 0s^emmt8 however, both the // form and the 
^4 form occurred. An the of hi* 

Mr Fryer came to the that the 

difference is one of a AH 

mimetic females the X but the II 



vn] THE CASE OF PAPILIO POLJTES 89 

females contain in addition a factor which, we may 
call Y. The function of the 7 factor is to carry the 
change made by the X factor a step further, and to 
turn the A form of female into the H form. Y is a 
modifier of X, but unless X is present Y can produce 
no effect. All the different individuals which are to be 
found among P. polytes in Ceylon may be represented 
as follows : 



3$ 


AT $? 


A& 


T<$ 


lixxYY 


iixx YY 


_ 


, - - , 


li xx Yy 


ii xx Yy 








lixxyy 


ii xx yy 








liXxYY 





. 


UXxYY 


li Xx Yy 





. 


ii Xx Yy 


li Xx yy 
liXXYY 





viXxyy 


viXXYY 


liXXYy 








UXXYy 


UXXyy 





iiXXyy 






In this way is offered a simple explanation in terms 
of three Mendelian factors which serves at once to 
explain the various results of the breeding experiments, 
and the fact that intermediates between the different 
forms of female are not found. 

The only other experiments comparable with these 
on P. polytes are some made by Jacobsen on Papilio 
memnon in Java 1 . Here again there are three forms 
of female, one of which, laomedon, is something like the 
male, while the other two, agenor and achates, are 
quite distinct. Of these three achates, unlike the male 
and the other two females, is tailed, and resembles 

1 Tijdscfar. voor ISntomologie, vol. 53, 1909. A more accessible 
account is given by de Meijere, Zeit. /. vnd/ukt, Abatcvmm. u. Ver&rbimg8~ 
lehre, vol. 3, 1910. 




90 THE CASE OF PAPILIO frn 

the species Papilio coon- which belong* to the 
presumably distasteful group a* P. artVotorAiVrr. The*e 
experiments of Jacobaen'* art* not *o complete n* the 
series on P. polyte*, but Profefwor de Metjere and 

Mr Fryer have both pointed out, that, they are 
of being interpreted on the wimple linen. 

Another instance of experimental involving 

polymorphism and mimicry in the* female ex In 
of the African Papilio dardanw* but the in 
complicated by the greater number of female form* 
(of. pp. 30-33), The too, are far morn 

than in the other two but HO far m they go 

there is nothing to preclude an explanation 
eventually arrived at on similar linen 1 , 

And now wo may consider briefly the of 

these experimenta on the theory of mimicry. Through- 
out the work no individual* intermediate between the 
three well-marked forma of with. 

There is no difference in th hetero- 

zygous and the homozygon* mimetic 
they belong to the A or to the II form. The 
X, whether inherited from both or from 

only, produces its full and the in 

true of the action of the Y. the 

generally accepted hypothesis an to the of 

these mimette that tiwy 

been brought about through 'the 
of natural selection accumulating 

1 For further iafosmtirtfott MM Poultoo, jfttf. Jte, IW 

ftad vorioua notoi la Pirn nf. 5ae j^omi. u iW 



vn] THE CASE OF PAPILIO POLJTES 91 

Professor Poulton, for example, a prominent exponent 
of this school, considers that the A form of female was 
first evolved gradually from the M form, and later on 
the H form came by degrees from the A form. If this 
be true we ought, by mingling the M germ plasm with 
the H germ plasm and by subsequently breeding from 
the insects produced, to get back our series of hypo- 
thetical intermediates, or at any rate some of them. 
We ought as it were to reverse the process by which 
the evolution of the different forms has taken place. 
But as is shewn by the experiment of Mr Fryer, which 
was quoted above, nothing of the sort happens. 

From experiments with cultivated plants such as 
primulas and sweet peas, we have learnt that this 
discontinuous form of inheritance which occurs in 
P. polytes is the regular thing. Moreover, we have 
plenty of historical evidence that the new character 
which behaves in this way is one that has arisen suddenly 
without the formation of intermediate steps. The 
dwarf " Cupid" form of sweet pea, for instance, behaves 
in heredity towards the normal form as though the 
difference between them were a difference of a single 
factor. It is quite certain that the " Cupid " arose as 
a sudden sport from the normal without the inter- 
vention of anything in the way of intermediates. And 
there is every reason to suppose that the same is true 
for plenty of other characters involving colour and 
pattern as well as structure, both in the sweet pea, 
the primula, and other species. Since the forms of 
polytes female behave in breeding like the various 



92 THE CASE OF* PAP I MO [cit. vn 

forms of sweet pea and primula there in every 
to suppose that they arrwf in the way, that in to 

say, as sudden sports or mutation* not by the 
gradual accumulation of slight difference*. 

But if wo take this view, which w certainly 

consonant with the evidence before tin, we munt 

to natural selection a different from which is 

generally ascribed to it W cannot mipiKMie 

O ** 

natural selection, hai played any part in the 
of a mimetic likeness. The turner! tip middtmly 

as a sport quit independently of m*-!eetion. 

But although natural selection may have had nothing 
to do with its production, it may 
come into play in connection with the of 

the new form. If the new form advan- 

tage over the pre-existing one from which it 

C? ** *"*! * ls? ff 

is it not conceivable that natural gpfoetion will 
into operation to render it the pntdominant 

To this question w shall try to find AH In 

the next chater. 




CHAPTER VIII 

THE CASE OF PAPILIO POLTTE8 (con*.) 

IT was suggested in the last chapter that if a new 
variation arose as a sport as a sudden hereditary 
variation and if that variation were, through resem- 
blance to a different and unpalatable species, to be more 
immune to the attacks of enemies than the normal 
form, it was conceivable that the newer mimetic sport 
would become established, and in time perhaps come 
to be the only form of the species. We may suppose, 
for example, that the A female of P. potytes arose 
suddenly, and that owing to its likeness to the pre- 
sumably distasteful P. a/ristolochiae it became rapidly 
more numerous until in some localities it is the common- 
est or even the only form. However, before discussing 
the establishing of a mimetic form in this manner we 
must first deal with certain general results which may 
be expected to follow on a process of selection applied 
to members of a population presenting variations 
which are inherited on ordinary Mendelian lines. 

Let us suppose that we are dealing with the in- 
heritance of a character which depends upon the pre- 
sence of the genetic factor X ; and let us also suppose 
that the heterozygous form (Xx) is indistinguishable 




94 THE CASE OF PAP ILK) POLYTKfl far. 

from the homozygous form (XX) in appearance. In 
other words the character dependent, upon A" exhibit* 
complete dominance. With regard to X then all the 
members of our population mt iwlong to one or 
other of three classes. They may be homozygcniH (A* A*) 
for X, having received it from both imrentu, or they 
may be heterozygouH (Xx) bccautte they have reeeivec! 
it from only one parent, or they may be devoid of A", 
i.e. pure reeessives (xx). An interesting queHtion 
as to the conditions under which a {xjpulAtirtn con- 
taining these three kinds of individual* remain** ntable. 
By stability is meant that with the three kind* mating 
freely among themselves arid being all equally fertile, 
there is no tendency for the relative) pro|K>rtiit*i of 
the three classes to be disturbed from gttmnttton to 
generation. The question looked into ttttftitt 
ago by G, H. Hardy, who allowed that if the mtxtxi 
population consist of p IX individual % Ix in- 
dividuals and r xx individuals, the imputation will Us 
in stable equilibrium with to t!i rotative pro- 

portions of these three i long tut tho equation 

pr ^ 2 is satisfied 1 , 

Now let us suppose that in of equality of 

eoaditions selection is in favour f 

individuals which exhibit the dominant It 

has been shewn by Mr Norton that even if tat* 
exercised were slight tho rcwult in the end would to 
that the form would entirely 

The total time required for 

, July, 



^ 



vm] THE CASE OF PAPILIO POLYTES 95 

depend upon two things, (1) the proportion of domi- 
nants existing in the population before the process of 
selection began, and (2) the intensity of the selection 
process itself. Suppose, for example, that we started 
with a population consisting of pure dominants, hetero- 
zygotes, and recessives in the ratio 1:4:4. Since 
these figures satisfy the equation pr = q z , such a popu- 
lation mating at random within itself is in a state of 
stable equilibrium. Now let us suppose that the 
dominant form (including of course the heterozygotes) 
is endowed with a selection advantage over the re- 
cessives of 10%, or in other words that the relative 
proportion of the recessives who survive to breed is 
only 90% of the proportion of dominants that sur- 
vive 1 . It is clear that the proportion of dominants 
must gradually increase and that of the recessives 
diminish. 

At what rate will this change in the population take 
place? Mr Norton has worked this out (see App. I) 
and has shewn that at the end of 12 generations the 
proportions of pure dominants, heterozygotes, and re- 
cessives will be 1:2:1. The population will have 
reached another position of equilibrium, but the pro- 
portion of recessives from being four-ninths of the 

1 If for example there were 5000 dominants and 4000 reoeseives, 
and if only half of the population survives to mate, then we should 
be left with 2500 dominants and 2000 recessives as parents of the next 
generation. But if there were also a 10 % selective disadvantage 
working against the recessives, their numbers would be further reduced 
from 2000 to 1800 and the proportion of dominants to recessives would 
be changed from 5 : 4 to 25 : 18. 



of 10% operating against tne recewuves WHJ reauoe 
their numbers in 70 generations from nearly one-half 
of the population to less than one-fortieth, 

With a less stringent selective rate the number of 
generations elapsing before this result is brought about 
wiH be larger. If, for example, the aeiective rate in 
diminished from 10% to 1% the number of genera- 
tions necessary for bringing about the t 
nearly 700 instead of 70 roughly ten times ON great. 
Even so, and one can hardly of a I % detective 
rate as a stringent one, it is remarkable in how brief 
a space of time a form which is discriminated 
even lightly, is bound to disappear. Evolution, in no 
far as it consists of the supplanting of one form by 
another, may be a very much more rapid Uian 
has hitherto been suspected, for natural if 
appreciable, must be held to operate with extra* 
ordinary swiftness where it ia given varia- 
tions with which to work. 

We may now consider the bearing of theo- 

retical deductions upon the of Papilio in 

Ceylon. Here is a case of a population living and 
breeding together under the conditions* a popu- 

lation in which there are three upon 

the presence or abseaee of two X and Y , 




vin] THE CASE OF PAPILIO POLJTES 97 

exhibiting ordinary Mendelian inheritance. For the 
present we may consider one of these factors, X, which 
involves the proportion of mimetic to non-mimetic 
forms. It is generally agreed among observers who 
have studied this species that of the three forms of 
female the M form is distinctly the most commonj 
while of the other two the H form is rather more 
numerous than the A form. The two dominant 
mimetic forms taken together, however, are rather more 
numerous than the recessive M form. The most 
recent observer who studied this question, Mr Fryer, 
captured 155 specimens in the wild state as larvae. 
When reared 66 turned out to be males, while of the 
females there were 49 of the two mimetic forms and 40 
of the M form, the ratio of dominants to recessives 
being closely 5 : 4 1 . Now as has already been pointed 
out the ratio 5 : 4 of dominants and recessives is 
characteristic of a population exhibiting simple Men- 
delian inheritance when in a state of stable equilibrium. 
The natural deduction from Mr Fryer's figures is that 
with regard to the factor that differentiates the mimetic 
forms from the non-mimetic, the potytes population is, 
for the moment at any rate, in a position of stable 
equilibrium. This may mean one of two things. 
Either the population is definitely in a state of equi- 
librium which has lasted for a period of time in the past 

1 As these larvae were for the most port found simply over a consider- 
able timo it follows that they are the offspring of different females 
and represent the relative proportions of the three forms in the general 
population. 

P. M. 7 




i II 



98 THE CASE OF PAP ILK) POLYTES [cit. 

and may be expected to endure for a further period in 
the future, or else the population is in a condition of 
gradual change as regards the numerical proportion of 
rnimetics and non-mimeticR, programing towards the 
elimination of the one or the other, the prawn t state 
of equilibrium being merely tratwitory and accidental 
In this connection a few scrape of historical evidence 
are of interest. Of the various forms of /. po/i/Ms the 
A form of female was the first to he ckwribed in 1758, 
and not long after (1776) the H form wa registered as 
a species under the name of Papilio Kqur* Trojanu* 
romulus. Later on the female resembling the male 
found its way into the literature a Papilio pammon. 
From the fact that the mimetic forms were known Iwfnro 
the non-mimetic, it is unlikely that they can have fw^n 
scarce a century and a half ago. AH P. potyte* cer- 
tainly produces at least four broods a year in Oylon 
this period of time represents something like* 600 
generations in the life of the and wo 

already seen that even if the mimetic forms have but 
a 1 % advantage over the non-mimetio the proportion 
of the latter would decrease from nearly equality 
down to but I in 40 in about 700 generations. 
Actually for P. polytm the would not bo m 

marked because the male is non-mimetic. Owing to 
this peculiar feature the rapidity of in the 

proportion of the different forms is reduced" to about 
one-half of what it would b if the were also 

mimetic. Nevertheless the change from newly equality 
to about one non-mimetic in 40 would have 



vra] THE CASE OF PAPILIO POLYTES 99 

during the time P. polytes has been known if a 2% 
selection advantage had operated during that period 
in favour of the mimetic. If there has been any 
appreciable selection going on during that time mi- 
metics must have been far rarer when the species was 
first discovered, but the fact that both the mimetic 
forms made their way into collections before the 
non-mimetic tells distinctly against this supposition. 
Nor is there any reason to suppose that the non-mimetic 
form has been dwindling in numbers relatively to the 
mimetics during the last half century. Moore 1 in 1880 
records an earlier observation of Wade's that ** These 
three butterflies are very common, especially those of 
the first form; the second being perhaps least so." 
The first form alluded to is the M form, and the 
second is the A form, so that at the time Wade wrote 
the relative proportions of these three forms must 
have been very much what they are to-day. Even 
during half a century and with such a relatively weak 
selection rate as 2% in favour of the mimetics, the 
proportion of non-mimetics should drop from about 
4 : 5 down to about 1 : 5. Therefore we must either 
infer that in respect of mimetic resemblances natural 
selection does not exist for P. polytes in Ceylon, or else 
we must suppose its force to be so slight that in half a 
century -certainly, and perhaps in a century and a 
half, it can produce no effect appreciable to the neces- 
sarily rough method of estimation employed. 



The Lepidoptera of Ceylon, 1880, 



72 



100 



[CH. 



It may, however, bo argued that even an exceedingly 
low selection rate is able to bring about the elimination of 
one or other type provided that it acts for a sufficient ly 
long time. This is perfectly true. A selective rate 
of '001% would reduce the proportion of receiwivw* 
to dominants from 4 : 5 down to 1 : 40 in the onurao 
of about 1,400,000 generations where the mimetic 
resemblance is already established. Such a form of 
selection entails the death of but one additional non- 
mimetic in 100,000 in each generation, If, however* 
the mimetie resemblance in not fully establislnnl and 
the mimic bears only what supporters of the mimicry 
theory term a "rough" resemblance to the mcxlel, it is 
clear that it will have far leaa chance of being mistaken 
for the model Its advantage as compared with the 
non-mimetic form will bo very much lew. Even 
supposing that the slight variations concerned are in- 
herited, an intensity of selection which would produce 
a certain change in 1,400,000 generations whore a 
mimetic resemblance is already established bo 

supposed to take an enormously greater time where 
an approach to a model has to from a 

" rough " resemblance, 

From the data as to the relative proportion* of the 
polymorphic females of P. during the and 

at present, and from the behaviour of their different 
forms in breeding, the following conclusions only can 
be drawn, Either natural selection, from the point of 
view of mimicry, is non-existent for this in 

Ceylon, or else it is so slight as to be in half a 



vin] THE CASE OF PAPILIO POLYTES 101 

century to produce an appreciable diminution in the 
proportion of non-mimetic females. For even if the 
mimetic resemblance brings about but the survival of 
one additional protected form in 100 as compared with 
the unprotected, this means a marked diminution in 
the proportion of M females in 50 years a diminution 
such as there are no grounds for supposing to have 
taken place. 

It has been argued that in populations exhibiting 
Mendelian heredity even a relatively low selection rate 
must bring about a rapid change in the constitution of 
a mixed population. Have we any grounds for sup- 
posing that populations of this sort can undergo such 
rapid changes? In cases where mimetic resemblances 
are involved we have no examples of the sort. But 
some interesting evidence as to the rate at which a 
population may change is to be gathered from the 
study of melanism in certain moths. It is well 
known that in some parts of England the common 
peppered moth, Amphidasys "betularia has been almost 
entirely supplanted by the darker melanic form double- 
dayaria. It first made its appearance near Manchester 
in 1850, and from that centre has been , gradually 
spreading over northern England, the Midlands, and 
the south-eastern counties. At Huddersfield, for 
instance, fifty years ago only the type form betularia 
existed; to-day there is nothing but doubledayaria. 
In Lancashire and Cheshire the type is now rare. 
On the continent, too, there is the same story to 
be told. The melanic form first appeared in Rhenish 



102 



ff'IL 



Prussia in 1888; to-day it is much more* abundant than 
the older type. There, too, it in spreading wiHfwitrde 
and southwards to Thuringia, to Saxony f to Silwia. 
What advantage this new dark form has over the* oldir 
one wo do not know 1 . Some advantage*, however, it 
must have, otherwise it could hardly supplant brtttlarta 
in the way that it is doing. From our pratent Htaud- 
point two things are of interest in the wine* of flu* 
peppered moth the rapidity with whieh the rlmnge 
in the nature of the population has taken pliifc% mul tlw 
fact that the two forms exhibit Montfolian hi*n*dity, 
doubledayaria being dominant and Iwtutariti rmwlvi* 51 . 
Moreover, mixed broods have been reared from wild 
females of both sorts, and so fur a is known the* two 
forms breed freely together where they >-txwt. This 
ease of the peppered moth shew how swiftly it change 
may eomo over a species 8 . It w not at alt improbable 
that the establishing of a new variety at the* 
of an older one in a relatively short of time is 

continually going on, especially in tropical where 

1 From the experience of bnwdttm it would avppMr that tin* tf*4anJ<) 
form is somewhat hardier, at any rate in captivity. 

8 Intermediate! may alao ooour In (of. f iowot*r. 

ofOnnetioi, vol. 3, no. 4, 1014), 

An intentting ease of a amite rt hm reotmUy bN>n fiIiIWil 
by Hftsebroik <JWe t/tmctutu, 1613, p. 10*0). A nwlnmo fctrm *tf th* 
moth, Oymatoptmu or, uddaaly appeared nmr Htwnbtirg tn iifii. 
This new form, to which tha nmm wm glvwi, 



, 

the predozoiiiaat om. In 1011-101S ovr 90 % of tl mocha 
from oaterpillaw taken In the open worn of the farmt **r 

were any intwmediatoi found between It and the form, 

mterimwts wwe ato mMe whioh anew (hat tJ 
M a domiawat to the original type form. 



vm] THE CASE OF PAPILIO POLYTES 103 

the conditions appear to be more favourable to exuber- 
ance of variation and where generations succeed one 
another in more rapid succession. At present, however, 
we are without data. A form reported by an old col- 
lector as common is now rare ; a variety once regarded 
as a great prize is now easily to be found. Such to-day 
is the sort of information available. For the solution 
of our problem it is, of course, useless. The develop- 
ment of Mendelian studies has given us a method, 
rough perhaps but the best yet found, of testing for 
the presence, and of measuring the intensity, of natural 
selection. Much could be learned if some common 
form were chosen for investigation in which, as in 
P. polytes, there are both mimetic and non-mimetic 
forms. Large numbers should be caught at stated 
intervals, large enough to give trustworthy data as to 
the proportions of the different forms, mimetic or non- 
mimetic, that occurred in the population. Such a 
census of a polymorphic species, if done thoroughly, 
and done over a series of years at regular intervals, 
might be expected to give us the necessary data for 
deciding whether the relative proportion of the different 
forms was changing whether there were definite 
grounds for supposing natural selection to be at work, 
and if so what was the rate at which it brought the 
change about. 




CHAPTER IX 

THE BNBMIE8 OF BUTTBRFLIK8 

THE theory of mimicry demands that butterflies 
should have enemies, and further that those onemira 
should exercise a certain discrimination in their attackM, 
They must be sufficiently observant to notice the 
difference between the mimetic and the non-mimetic 
form j they must be sufficiently unobservant to conf une 
the mimetie form with the unpalatable mortal* And, 
of course, they must have enough of to 

dislike the unpalatable and to appreciate the palatable 
varieties. What these enemies are and whether thf*y 
can be supposed to play tho part required of wo 

may now go on to consider. 

Butterflies are destroyed in the imago princi- 

pally by three groups of enemies 
lizards, and birds. It is known that monkey* 
devour butterflies to some extent, but such 
as they inflict is almost certainly amall in 
with that brought about by the three group already 
mentioned. In view of the very different of 

these groups it will be convenient to thorn 

separately. 



OH. ix] THE ENEMIES OF BUTTERFLIES 105 

I. Predaceous Insects. Butterflies are known to 
be preyed upon by other insects of different orders, 
and a considerable number of observations have 
recently been gathered together from various sources 
and put on record by Professor Poulton 1 . These 
observations shew that butterflies may be devoured by 
mantids, dragon-flies, and blood-sucking flies of the 
families Empiidae and AsiMae. For mantids the 
records are scanty, but they have been observed to 
kill presumably distasteful forms as often as those 
which are considered palatable. An interesting set 
of experiments was made by G. A. K. Marshall on 
captive mantids in Africa 2 . Of the eleven individuals 
representing several species with which he experi- 
mented, some ate every butterfly offered, including the 
distasteful Danaines and Acraeines. Others, however, 
shewed some distaste of the Acraeines and would not 
devour them so freely as butterflies of other species. 
There are no grounds, however, for supposing that the 
mantids had any appreciation of the warning color- 
ation of the Acraeines. Whether completely eaten or 
not the Acraeines were apparently sufficiently damaged 
to prevent their taking any further part in the pro- 
pagation of their species. Warning coloration is not 
of much service to its possessor who has to be tasted 
and partially eaten before being eventually rejected. 
Even if some mantids shew distaste of certain unpalat- 
able butterflies, that distaste is probably seldom 

1 Trans. Snt. Soc. Lond. 1907. 
8 Trcms. Ent. Soc. Lond. 1902. 



106 THE ENEMIES OF BUTTKRF.LI EH [CH. 

exercised with a gentleneas flufiicient to enmtrc that the 
butterfly reaps the reward of its cliHagrowble nature. 
And unless, of courBaj the butterfly i allowed to tin HO 

the enemy can play no part In tin* production or 
maintenance of a mimetic rcHenihlancc. 

What is true for mantida i probably atari true* for 
the other groups of predaceouH inHWt*. Drugntt-fHrH 
and wasps have been recorded an attacking the* din- 
tasteful as well as butterflies of unprot*rtxl grottg>*, 
Among the most serious em;imc*H of butt*H!irH must 
probably be reckoned the blood-Mucking AHiiidn, Thfw 
powerful and ferocious flies buit^rfiicM ?t f lit* wing 
with their strong clawn and plunge their pn>!KwiH into 
the thorax. Apparently they inject Home* nwift juitsiiii, 
for the butterfly is instantly paralyticd, nor in t.!itri' any 
sign of struggle. The Aiiilid flic*H oi! with iU vietim, 
sucking the juices as it goea There can be* no doubt 
in the mind of any one who iiaa watched cnmturtm 

hawking buttorflioH that their natural art* Miie?h 111 
to enable them, to exercise dimnnmmtmn In their fwni 
Most insect life IH at their mercy but they apptnr to 
exercise no choice, ieisdng and devouring tlict 
flyi.ng thing that comes within r&ach. Cbrtatnly 

as regards butterflies palatability or the 
no difference, and they are known to feed indiiK 
ately both upon the evil-flavoured and ujMin tlia 
Taking it aH together the evidence is that w can- 
not suppose predaceoua to pay any attention to 

warning colours, and, therefore, we cannot thorn an 

playing any part in connection with 



ix] THE ENEMIES OF BUTTERFLIES 107 

II. Lizards. In those parts of the world where 
lizards of larger size are abundant there is plenty of 
evidence that certain species are very destructive to 
butterfly life. As might be expected this is especially 
true of forms which are either arboreal or semi-arboreal 
in habit. Among the reptiles of Ceylon, for example, 
are several species of the genus Calotes, of which two, 
C. ophiomachus and C. versicolor, are particularly abun- 
dant. In appearance and habits they are not unlike 
chameleons though far more active in their movements. 
Like chameleons, too, they are able to change colour, 
and the fact that they can assume a brilliant scarlet 
hue about the head and neck has probably led to their 
popular name of "blood-suckers." It is not impossible 
that the assumption of this scarlet coloration may 
serve as a lure to bring insects within range. These 
lizards have often been observed to seize and devour 
butterflies. Moreover, it is a common thing to find 
butterflies with a large semi-circular patch bitten out 
of the hind wings, and there is little doubt but 
that such injuries have been inflicted by lizards. 
There is, however, no evidence to suggest that they 
exercise any discrimination in their choice of the 
butterflies which they attack. This is borne out by 
their behaviour towards various species offered to 
them, both when at liberty and when caged. In an 
ingenious series of experiments Col. Manders brought 
various butterflies within reach of a Calotes by the 
help of- a fishing-rod and a long line of fine silk, by this 
means simulating natural conditions as far as possible. 



108 THE ENEMIES OF BUTTERFLIES [CH. 

He found that the lizards ate the so-called distasteful 
forms such as Dariais chrysippus, Euploea core, Acraea 
violae, and Papilio hector, as readily as the presumably 
more palatable forms 1 . In captivity, too, they will 
take any butterfly as readily as another. Experiments 
by Finn 2 and by the writer 3 proved that they ate 
Danaids, Euploeas, and Papilio aristolochiae without 
any hesitation so long as the insects were alive and 
moving. When, too, a mixture of different species, 
some with and some without warning coloration, was. 
given to them all were eaten, nor was there any dis- 
crimination evidenced in the order in which they were 
taken. The lizard simply took the first that came 
within reach and went on until the whole lot was 
devoured, wings and all. 

Some experiments by Mss Pritchett on the American 
lizard Sceleporus floridanus point to the same con- 
clusion 4 . She found that it took without hesitation 
any butterfly offered to it including the presumably 
distasteful models Danais archippus and Papilio phil- 
enor (of. pp. 45 and 49). On the other hand, another 
species of lizard with which Miss Pritchett experimented, 
Gerrhonotus infernalis, refused all the butterflies offered 
to it, though it fed freely on Orthopterous insects as 
well as on spiders and scorpions. 

It seems clear from these various observations and 

1 Proc. ZooL Soc. 1911. 

8 Journ. Roy. Asiat. Soc. Bengal, vol. 65, 1897. 

3 Spolia Zeylanica, 1910. 

4 Biological Bulletin, vol. 5, 1903. 



ix] THE ENEMIES OF BUTTERFLIES 109 

experiments that certain lizards devour butterflies 
freely, but that they do not exercise any discrimination 
in the species which they attack. All are caught and 
devoured indiscriminately, so that in spite of the fact 
that such lizards are among the most serious enemies 
of butterflies we cannot suppose them to play any part 
in establishing a mimetic resemblance. 

III. Birds. The relations which exist between 
butterflies and their bird enemies have for many years 
been the subject of keen discussion. It is generally 
recognised that if mimetic resemblances become estab- 
lished through the agency of discriminating enemies 
those enemies must be birds. Hence those interested 
in the question of mimicry have for some years past 
turned their attention to birds more than to the other 
enemies of butterflies. That many birds systemati- 
cally feed on butterflies is a fact that does not admit 
of doubt. It is true that, as Mr Marshall points out 
in the valuable paper in which he has summarised the 
evidence 1 , ^observations of birds eating butterflies are 
relatively scanty. Though, as he points out, this is 
equally true for other groups of insects besides butter- 
flies, bird attacks on butterflies, owing to the con- 
spicuous nature of the victim, are much more likely to 
attract attention than attacks on other groups. We 
are still without much information as to the extent to 
which birds destroy butterflies and as to whether they 
shew any decided preference for certain species over 
others. A careful examination of the contents of the 

1 Trans. Ent. Soc. Lond. 1909. 



110 THE ENEMIES OF BUTTERFLIES [cm. 

stomachs of largo numbers of insectivorous bird* in a 
tropical area would go some way towards deciding the 
matter, but at present such information in lacking. 
We have to rely upon the existing observations of birds 
attacking butterflies in the wild stato> and upon certain 
feeding experiments made with captive birds. 

Observations on birds attacking butterflies where* 
mimetic forms occur have been nmdo altnoRt entirely 
in certain parts of Africa, in India, and in CVylon. For 
Africa, Marshall has collected some forty-nix obser- 
vations of which almost half are concerned with 
Pierines. The remainder include four instances of 
attacks on species of Acraea, ft gemts which on tlw 
mimicry theory must be regarded as among the most 
unpalatable of butterflies, 

The records from the Indo-Malayan region (prin- 
cipally India and Ceylon) are somewhat raorit numerous 
and here again more than one-third of them rc*fw to 
Pierines. Among the. other** arc records of the din- 
tasteful forms JSuploea core, K. raffiem, violac, 
and Papilio hector being token and dkwouml. 

There is one interawting which to 

suggest that Swinhoe'e Bee-Eater (MeliU&phagu* #*vin~ 

*wf*>&r 9, sf ^ 

hoei) may exercise that discrimination in the buttwfiii'H 
it attacks which is demanded on the mimicry theory. 
Lt.-Col B-ingham on one occasion in Burma noticed 
this species hawking butterflies. He that they 

took PapiUo mthmiw, P. mrpedm* 
Cyrestis thyodamaa, aad Terios and probably abo 

species of the geaera Priomrw, (Fierinw), 




ix] THE ENEMIES OF BUTTERFLIES 111 

Junonia and Precis (Vanessids). And he goes on to 
say; "I also particularly noticed that the birds never 
wont for a Danais or Euploea, or for Papilio macareus 
and P. xenocles, which are mimics of Danais, though 
two or three species of Danais, four or five of Euploea, 
and the two above-mentioned mimicking Papilios 
simply swarmed along the whole road 1 ." 

Marshall also quotes a case of attack by a green 
bee-eater on a Danais in which the butterfly was caught 
and subsequently rejected, after which it new away. 
Little stress, however, can be laid upon this case in 
view of the more recent data brought together by 
Col Manders and Mr Fryer, Discussing the attacks 
of birds on butterflies in Southern India and Ceylon, 
Col. Manders gives the following quotation 2 from a 
letter of Mr T. N. Hearsy, Indian Forest Service : 

" Coimbatore, 6. 8. 10. ... I have frequently seen 
the common green bee-eater (Merops viridis) and the 
king-crow (Buchanga atra) take butterflies on the wing, 
the butterflies being CatopsiUa pyranthe, G. florella, 
Terias hecabe and Papilio demoleus. The bee-eater 
I have also seen taking Danais ckrysippus and Danais 
septentrionis, and I remember to have been struck 
with their taste for those latter. ..." 

Col. Manders also brings forward evidence for these 
Danaids and Euploeas being eaten by Drongos and by 
the paradise flycatcher. Still more recently an inter- 
esting contribution to the matter has been made by 

1 Trans, Ent, Soc. Lond. 1902. 
* Trans. Ent, Soo. Lond, 1911. 



112 THE ENEMIES OF BUTTERFLIES [CK. 

Mr J. C. F. Fryer 1 , The Ashy Wood-swallow (A rtamwt 
fuscus) had been recorded on two occasions as having 
attacked JEuploea core. Mr Fryer was fortunate in 
coming across this bird in the gardens at Peradeniya, 
near Kandy, at a time when Kuploea corn and Datmm 
septentrionis wereparticularlyabundant, and lit* watched 
a number of thorn systematically hawking thene pre- 
sumably unpalatable species. A ho ohwrvcH, "in 
Ceylon a resemblance to the genera Dannw and K-uplom 
is doubtfully of value; in fact in the neighbourhcKid of 
Wood-swallows it is a distinct danger." Fryer 
noted that the mimetic forms of P. polytw were taken as 
well as the non-mimetic* 

For tropical Central and South America, that other 
great region where mimetic forms are numeroufi, thwro 
are unfortunately hardly any records of butterHie* 
attacked by birds, Bates stated that the Pierinett were 
much persecuted by birds, and his statement in con- 
firmed by Hahnol, but exact observation* for thii 
region are remarkably scanty. Belt obnerved n pair 
of birds bring butterflies and dragon-fife* to their 
young, and noticed that they brought 110 Heltaonii to 
the nest although these swarmed in the neighbourhood*. 
On the other hand, MX W. Sohaus 1 , from an 
of many years spent in the of America, 

considers that the butterflies of this a hardly, 

if ever, attacked by birds, 



Zool 8&G, 1018, 

8 A NttfAmMst in Niatmffm, 1874, p. SI 8. 

9 I ff Oongr. Intemwt. $Mnknwlffai, mil, 



ix] THE ENEMIES OF BUTTERFLIES 113 

For North America Marshall records over 80 cases 
of birds attacking butterflies. Among them is an 
interesting record of a bird seizing and rejecting a 
specimen of Anosia plexippus (=Danais archippw), one 
of the few Danaines found in this region. 

It must be admitted that the data at present 
available with regard to the attacks of birds upon 
butterflies under natural conditions are too meagre to 
allow of our coming to definite conclusions on the 
points at issue. It is safe to say that a number of species 
of birds have been known to attack butterflies that a 
few out of the number feed upon butterflies system- 
aticallythat some of the most persistent bird enemies 
devour the presumably protected forms as freely as 
the unprotected but that in a few instances there is 
some reason for supposing that the bird discriminates. 
Beyond this it is unsafe to go at present. 

In attempting to come to a decision as to the part 
played by birds in the destruction of butterflies an 
evident desideratum is a knowledge of the contents of 
the stomacis of freshly killed birds. Unfortunately 
few systematic observations of this nature exist. 
G. L. Bates 1 , when collectmg in the Southern Came- 
roons, noted the stomach contents of a considerable 
number of birds. The remains of beetles were re- 
cognised in 213 cases : Orthoptera in 177 : ants in 57 
(mostly in stomachs of birds of the genus Dendromus) : 
other Hymenoptera in 8: coccids in 32: bugs in 19: 
white ants in 31 : slugs and snails in 24 : spiders in 85 

i Ibis, 1911. 

p, M. 3 



114 



[CIL 



(mostly in Sunbirds) : millipedes in 20 ; Imt in no tangle 
instance were the remain* of butt#diie* found. More 
recently Bates' account has boon criticized by Swynner- 
ton 1 who comment* on the difficulty of identifying 

butterfly remains as compared with thow of 
and grasshoppers. He that the- pellet* ejected 

by captive birds after a of btitU<rfiie* contain only 
fine debris which is vary difficult to identify. Further* 
he found that of twenty small bird rxeretn collected in 
the forest no than eighteen contained tuic! 

small wing fragments of tapidoptera, 

Some attention han been paid to the relation Im 
tween birds and butterflies* in this United State**, and 
under the auspices of tins Department of Agriculture 
a large number of birds' stomachs bavi !>* inv^Mti- 
gated. Careful examination of 40 ( (XX) Htomachii 

of birds shot in their natural lit tlte 

discovery of butterfly in but four* It cannot, 

therefore, b supposed that birds play muoh in 

connection with such mimetic an are 

found in North America (of, pp. 46-49). 
it is known that on of butter- 

flies may be destroyed by An 

is described by Bryant 2 of an in North 

California of Bugmm a of 

the tortoteeshelL The butterfly was so as to 

be a plague, and five of 

of its great abundance to prey upon it, 

1 IMi, 191S. 

1 Th Qtm&or, vol. 18, 1911, pp, 



ix] THE ENEMIES OF BUTTERFLIES 115 

his examination of the stomachs Bryant came to the 
conclusion that some 30 % of the food of these five 
species was composed of this butterfly. The stomachs 
of many other species were examined without ever 
encountering butterfly remains. Nor did field obser- 
vations support the view that any species, other than 
the five specially noted, ever attacked these butterflies. 
The case is of interest in the present discussion as 
evidence that the identification of butterfly remains 
in the stomachs of birds is by no means so difficult as 
some observers suggest. 

Besides this evidence derived from observations 
upon birds in the wild state some data have been 
accumulated from the experimental feeding of birds 
in captivity. Of such experiments the most extensive 
are those of Finn 1 in South India. He experimented 
with a number of species of insectivorous birds be- 
longing to different groups. Of these he found that 
some, among which may be mentioned the Kong-crow, 
StarMng, and Idothrix 2 , objected to Danaines, PapiUo 
arifftolochiae and DeUas eueharis, a presumably dis- 
tasteful Pierine with bright red markings on the under 
surface of the hind wings (PL II, fig. 1). In some cases 
the bird refused these forms altogether, while in others 
they were eaten in the absence of more palatable 
forms. The different species of birds often differed in 

1 Jo-urn. Aaiat. 800. Bengal, vol. 64, 1895, and vol. 60, 1897. 

8 Nevertheless a Liothrix is recorded as eating Danais plexippw 
and a ffluploea even though two male specimens of the palatable 
Elymniaa und/ularie were in the cage. 

82 



116 THE ENEMIES OF BUTTERFLIES [OH. 

their behaviour towards these three "nauseoua" forms, 
The HornbiU, for example, refused the Danainca and 
P. aristolochiae absolutely, but ate Delia* mctmrw, 
Some species again, notably the Bulbuls (Molpa*te#) 
and Mynahs, shewed little or no discrimination, but 
devoured the "protected" as readily aa the "un- 
protected" forms. Finn also states that " Papilio 
polytes was not very generally popular with birds, but 
much preferred to its model, I\ arixtolofikiar." 

In many of Finn's experiments both model and 
mimic were given to the birds simultaneouttiy HO that 
they had a choice, and he says that "in several 
I saw the birds apparently deceived by mimicking 
butterflies. The Common Babbler wan deceived by 
Nepheronia hippia 1 and Liothrix by ffypotimnttn mi#ip 
pus. The latter bird saw through the disguise of the 
mimetic Papilio polites, which, however, auftictant 
to deceive the Bhimraj and King-crow, I doubt if 
any bird was impressed by the mimetic appeamucu of 
the female Elymnim unduhns (of, PL IV, fig* 5), 
Finn concluded from his experiments that on the whole 
they tended to support the theory of and Wallace*, 

though he admits that the unpalatable forma 
commonly taken without the stimulus of hunger 

and generally without of dislike. Certainly it 

is as well to be cautious in drawing oonoiufuon* from 
experiments with oaptiv birds. The King-crow, for 
instance, according to Finn shewed a 
for Danaines in captivity; yet this 

1 A form closely rtsemfolrag P. c^lmlm on PI. 1, fig, I. 



ix] THE ENEMIES OF BUTTERFLIES 117 

species as feeding upon Danaines under natural con- 
ditions (cf. p. 111). 

A few further experiments with the birds of this 
region were carried out by Manders 1 in Ceylon. The 
results are perhaps to be preferred to Finn's, as the 
birds were at liberty. Manders found that the Brown 
Shrike (Laniua criatatw) would take butterflies which 
were pinned to a paling. In this way it made off with 
the mimetic females of Hypolimnas "bolina and JET. 
misippm, as well as with Danais chrysippiis and 
Acraea wolae which were successively offered . to it. 
Evidently this species had no repugnance to unpalat- 
able forms. Manders also found that a young Mynah 
allowed complete liberty in a large garden would eat 
such forms as Acraea violae and Papilio hector. As the 
result of his experience Manders considers that the 
unpalatability of butterflies exhibiting warning color- 
ation has been assumed on insufficient data, and he is 
further inclined to doubt whether future investigations 
will reveal any marked preference in those birds which 
are mainly instrumental in the destruction of butter- 
flies. 

A few experiments on feeding birds with South 
African butterflies are recorded by Marshall. A young 
Kestrel (Oerchneis naumanni) was fed from time to 
time with various species of butterflies. In most 
cases the butterflies offered were eaten even when they 
were species of Acraea. On the other hand Danais 
chrysippus was generally rejected after being partly 

1 Proc. Zool. Soc. Lond. 1911. 



118 THE ENEMIES OF BUTTERFLIES [OH. 

devoured. When first offered this unpalatable species 
was taken readily and it was only after it had been 
tasted that the bird rejected it. When offered on 
several subsequent occasions it was partly eatari each 
time, and the behaviour of the Ke&tre! did not 
that it associated a disagreeable flavour even with this 
conspicuous pattern. Another young Kestrel (C?crch~ 
neis rupicoloides) was also used for ex|>oriment. At 
first it would not take butterflies and at no time did 
it shew any fondness for them. Indeed it is doubtful 
from the way in which they seem to have shaped at 
the insects whether either of these Kestrels had had any 
experience of butterflies before the experiments began. 
A Ground Hombill with which Marshall abto ex- 
perimented ate various species, including Aemen, but, 
after crushing it, refused the only Danate chrymppm 
offered. It is hardly likely that this large omnivorous 
bird operates as a selecting agent in of mimicry, 

In an interesting paper published recently Me Alee 1 
discusses the value of feeding experiments with 
in captivity as a means of indicating their preference 
for different articles of diet. After reviewing the 
various evidence brought forward he concludes that 
the food accepted or rejected by captive animala is 
very little guide to its preferences under natural con- 
ditions, He points out that a bird in captivity not 
infrequently rejects what is known to form a main 
staple of its diet in nature, and that conversely it may 
eagerly accept something which, in the wild it 

1 ProG. Aead. Nat, Bd. PhtiatUpMa, 1019. 



ix] THE ENEMIES OF BUTTEEFLIES 119 

would have no opportunity of obtaining. Great cau- 
tion must, therefore, be exercised in the interpretation 
of feeding experiments made with birds in captivity. 

It appears to be generally assumed that colour 
perception in birds is similar to what it is among 
human beings, but some experiments made by Hess 1 
render it very doubtful whether this is really the case. 
In one of these experiments a row of cooked white 
grains of rice was illuminated by the whole series of 
spectral colours from violet to deep red. Hens which 
had been previously kept in the dark so that their 
eyes were adapted to light of low intensity were then 
allowed to feed on the spectral rice. The grains 
illuminated by green, yellow, and red were quickly 
taken, but the very dark red, the violet, and the blue 
were left, presumably because the birds were unable to 
perceive them. Again, when the birds were given a 
patch of rice grains of which half was feebly illuminated 
by red light and the other half more strongly by blue 
light, they took the red but left the blue. Previous 
experiment had shewn that with ordinary white light 
the birds always started on the best illuminated grains. 
It feeems reasonable to conclude, therefore, that in the 
red-blue experiment the feebly illuminated red grains 
were more visible than the far more strongly lighted 
blue ones. It might be objected that the birds had a 
prejudice against blue, but, as Hess points out, this is 
almost certainly not the case because they took grains 

1 0. Hess, Handbuch der v&rgl&ich&nden PJvyaiologie (herausgegeben 
von H, Winterstein), Bd, 4, 1912, p. 563, 



120 ' THE ENEMIES OF BUTTERFLIES [CH. 

which were very strongly illuminated with blue. 
Besults of a similar nature were also obtained from 
pigeons, and from a kestrel which was fed with pieces 
of meat lighted with different colours. 

On the whole these experiments of Hctw convoy a 
strong suggestion that the colour perceptions of birds 
may be quite different from our own, more PHfKurialiy 
where blue is concerned. Great caution i needed in 
discussing instances of mimicry in their relation to 
the bird, for we have no right to afummc that the* bird 
sees things as we do. On the other hand, it Is a matter 
of nrneh interest to find that in general blue* plays 
relatively little part in easea of mimetic ratom bianco 
among butterflies; some combination of a dark tint 
with either red, white, brown, or yellow Imhig far more* 
common. 

It will probably be admitted by most people that 
the evidence, taken all together, is hardly uufiictant 
for ascribing to birds that part in the establishing of a 
mimetic likeness which is required on the theory of 
mimicry, That birds destroy butterflies in 
numbers is certainly true, but it is no less true that sown 
of the most destructive birds appear to no 

choice in the species of butterfly attacked. They simply 
.take what comes first and is to oatch. It ii 

probably for this reason that the Wood-swallow 
chiefly on Euploeines and Danaines (of, p. 112), It 
is probably for this reason also that such a pro- 

portion of the records of attacks on under 

natural conditions refer to the Hermes; for owing to 



ix] THE ENEMIES OF BUTTERFLIES 121 

their light colour it is probable that the "Whites" are 
more conspicuous and offer a better mark for a bird in 
pursuit than darker coloured species. 

Mammals. Apart from man it is clear that only 
such mammals as are of arboreal habits are likely to 
cause destruction among butterflies in the imago state. 
Apparently there are no records of any arboreal 
mammal, except monkeys, capturing butterflies in the 
wild state, nor is there much evidence available from 
feeding experiments. But such evidence as exists is 
of considerable interest. As the result of feeding 
butterflies of different sorts to an Indian Tree-shrew 
(Tupaia femtginea) Finn 1 found that it shewed a strong 
dislike to Danaicls and to Papilio anstolochiae though 
it took readily Papilio demolem, Neptis kamampa, and 
Catopsilia (a Pierine). It is fairly certain that if the 
Tree-shrew is an enemy of butterflies in the wild state 
it is a discriminating one. 

The other mammals with which experiments have 
been made are the common baboon, a monkey (Cerco- 
pithems pygwythrm)* and a mongoose (Herpestes 
gal@ra)"~s,n by Marshall 2 in South Africa. The mon- 
goose experiments were few and inconclusive, nor is 
this a matter of much moment as it is unlikely that this 
mammal is a serious enemy of butterflies. 

The monkey ate various forms of Precis (a Vanessid), 
after which it was given Acraea halaU. This distaste- 
ful form was "accepted without suspicion, but when 

1 Jowrn. As, 800. Bengal, vol. 66 2 , 1S98. 
8 Trans. Mint. Soo. Lond. 1902. 



122 THE ENEMIES OF BUTTERFLIES [OH. 

the monkey put it into Ms mouth, he at once took it 
out again and looked at it with the utmoat surprise 
for some seconds, and then threw it away. Ho would 
have nothing to do with an Acraea caldarena which I 
then offered him 1 ." 

The experiments with the baboons were more ex- 
tensive. Two species of Acraea, hatttli and axina, 
were recognised when first offered and refused un- 
tasted. Danais chrysippm, on the other hand, was 
tasted on being offered for the first timo, and then 
rejected. This species was twice offorod BubncKjimntly 
and tasted each time before being rejected. Whim 
offered the fourth time it was rejected at night The 
baboon evidently learned to associate an unpleasant 
taste with the chrysippus pattern. At this stage it 
would have been interesting to have offered it HOMO 
well-known mimic of chrysippm, such m the female 
of Hypolimnas mimppna or the iraphonim form of 
Papilio dardanm, but this experiment was unfortunately 
not made. Marshall did, however, offer it at the name 
time a specimen each of Byblia ilithyia (a Vanewiid) 
and of Act-am axina to which it a general 

resemblance, The baboon took the former but ne- 
glected the latter altogether. The general resemblance 
between the two species was not sufficiently to 

deceive it. 

These experiments with mammals, though law in 
number, are of unusual interest. Should they be 
substantiated by further work it is not impossible 

,, loe. <*, p, 870. 



ix] THE ENEMIES OF BUTTERFLIES 123 

that, as a factor in the establishing of a mimetic like- 
ness, a stronger case may be made out for the monkey 
than the bird. The monkey apparently eats butterflies 
readily 1 : owing probably to a keener sense of smell it 
shews far less hesitation as to its likes and dislikes: 
its intelligence is such that one can easily imagine it 
exercising the necessary powers of discrimination; 
in short it is the ideal enemy for which advocates of 
the mimicry theory have been searching if only it 
could fly. As things are its butterfly captures must be 
made when the insect is at rest, probably near sunrise 
and sunset, and this leads to a difficulty. Most butter- 
flies rest with their wings closed. In many of the 
well-known cases of mimicry the pattern on the under 
surface of the mimic's wings which would meet the 
monkey's eye is quite different from that of its model. 
It is difficult in such cases to imagine the monkey 
operating as a factor in establishing a resemblance 
between the upper surfaces of the wings of the two 
unrelated species. On the other hand, some butterflies, 

1 In this connection may be quoted a letter from Capt. N. V. Neal 
near Lagos to Mr W. A. Lamborn which was recently published in the 
Proee&d&ngs of the Entomological Society. 

"You have asked me about monkeys eating butterflies. This is 
very common, as every native will tell you. I have seen it myself. 
The monkey runs along a path, sees some butterflies fluttering round 
some filth, goes very quietly, and seizes one by the wings, puts the 
solid part (body) into his mouth, then pulls the wings oflE. The poor 

butterfly goes down like any oyster The dog-faced baboon and the 

large brown monkey 'with a very long tail, which seems to be the most 
common species in this colony, are great butterfly-eaters. The little 
spider-monkey also considers a butterfly a treat, and prefers one to 
a spider." 



124 THE ENEMIES OF BUTTERFLIES [rinx 

e.g. Papilio poli/Ux, rest with wings outHpread, and 
there are rare cases, such a that of /'. laglaiz^i 
(p. 27), where the most Btriking point about the re- 
semblance is only to bo appreciated when the ieet 
are at rest with their wings clotted. In murh cane* it is 
conceivable that tho monkey may play a part hi the 
elimination of the non-mimetic element* of ft {uiiatable 
species which at tho same times pcwsmtinl a mimetic 
form closely resembling another Hpecien diHagrwable to 
the monkey's taste. A haK bt^n poitit.^c! out tarlier 
(p. 90) even a slight pertKXsution iiirtKjtcHl with adecjtmtc* 
discrimination will in time bring about A marked reult 
where tho mimetic HkeneHo w itlreaciy in <xi8U*w. It 
is not impossible therefore that the fwtiibiinhiiig of sttoli 
a likeness may often be due mop* to the diHt'iimitmtion 
of the monkey than to the mobility of tho bird. 



CHAPTER X 

MIMIOEY AND VARIATION 

IT is clear from the last few chapters that the 
theory of mimicry in butterflies with its interpretation 
of the building up of these likenesses by means of 
natural selection in the form of predaceous birds and 
other foes is open to destructive criticism from several 
points of view. The evidence from mimicry rings 
makos it almost certain that in some cases the resem- 
blance must be founded on an initial variation of such 
magnitude that the mimic could straightway be con- 
fused with the model Till the mimic can be mistaken 
for the model natural selection plays no part. The 
evidence from breeding suggests strongly that in certain 
cases (e.g. Papilio polytes) the likeness arose in the 
form in which we know it to-day. In such cases there 
is no reason for supposing that natural selection has 
had anything to do with the formation of the finished 
mimic. Considerations of this nature may be said to 
have destroyed the view, current until quite recently, 
that in the formation of a mimetic resemblance the 
exclusive agent was natural selection. During the past 
few years it has come to be admitted by the staunchest 
upholders of the theory of mimicry that natural 



126 



MIMICRY AND VARIATION 



[CH. 



' 



selection would not come into play until the would-be 
mimic was sufficiently like the model to be confused 
with it under natural conditions 1 . The part now 
often attributed to natural selection is to put a polish 
on the resemblance and to keep it up to the mark by 
weeding out those which do not reach the required 
standard. It is supposed that if natural detection 
ceases to operate the mimetic roaeinhlatice w gradually 
lost owing to the appearance of variation!! which arc 
no longer weeded out. An interesting ha# recently 
been brought forward by Carpenter 1 and explained on 
these lines: The Nymphalino Paeutdacraea tmryiuM is 
a polymorphic species found in Central Africa, In 
Uganda it occurs in several distinct forms which wort* 
originally supposed to be distinct specie**. Threw of 
these forms boar a marked resemblance to three Hfjecien 
of the Acraoine genus Planema* 

Mimic Model 

Paeudacraea eurytm Pfanemet 

Form habkyi* (PL VII t irawmta(PL VH, flg.2) 

figs, 6, 7) 

term (PL VII, fig. 8) tettus (PL VII, fig. 8} 
ofocura (PL VII, fig, 4) 

These different species occur round Victoria Nyanza 
and also on some of the islands in the 

1 Of. E. B. Bcraltoa In BitMk for Got, 1913, p. 801. 

9 Tram, Bnt. Soc. London, 1914, 

3 la the femftte fco&toyi, with rare exceptions, th 0! th 

male is replaced by white, wad it him weulwd the 
The female of P. mawritta $m wWto to of th of 

th male. 



X] 



MIMICRY AOT> VARIATION 



127 



interesting points are brought out by a comparison of 
the occurrence and variation of the species on the 
mainland with what is found on Bugalla Island in the 
Sesse Archipelago. On the mainland the Pseud- 
acraeas are abundant but the Planemas even more so, 
outnumbering the former by about 5 : 2 1 . Moreover, 
it is rare to find individuals more or less intermediate 
between the three forms, though they are known to 
occur. On Bugalla Island, however, a different state 
of things is found. The Pseudaeraeas are very abund- 
ant, whereas the Planernas, owing doubtless to the 
scarcity of their food plant, are relatively rare, and are 
very greatly outnumbered by the Pseudacraeas. At 
the same time the proportion of transitional forms 
among the Pseudacraeas is definitely higher than on 
the mainland. These facts are interpreted by Car- 
penter as follows: 

On the mainland where the models are abundant 
there is a vigorous action on the part of natural selection. 
The mimetic forms have a strong advantage and the 
non-mimetios have been gradually weeded out. But 
on the island, where the Pseudacraeaa outnumber the 
models, the advantage obtained through mimicry is not 
so great. The so-called transitional forms are little, 
if at aH, worse off than those closely resembling the 
scarce models, and consequently have as good a chance 
of surviving as any of the typical mimetic forms. On 

1 Ci Poulton, B. B., /* Oongr. Interned. d'BntomoL, BrullB 1011. 
This proportion, is founded on several hundreds caught at random, 
Observers are agreed that Ps&udaora&a is both a warier inseot and a 
stronger flyer than the various Planemas which it resembles. 



128 MIMICRY AND VARIATION 

the mainland, however, the enemieH of 
are well acquainted with the Plarutma models which are 
here common, and discriminate against individuals 
which are not close mimics of the Plancmaa. The 
result is that on the mainland transitional forms are 
scarcer than on the island. Natural selection main- 
tains a high standard for the mimetic like-now on the 
mainland owing to the abundance of the. rmxieJ ; but 
when the model is the likeness to be 

kept up to the mark strictly, and tendfl to become 
lost owing to the appearance of fresh variations which 
are no longer weeded out. 

Here it should ho stated that th various Pseud* 
aoraeas form a population in which the diffcnmt forms 
mate freely with one another* In the few breeding 
experiments that I)r Carpenter was able to make* he 
found that obscura could produce term, anil that 
tirikenma was able to give obmtra, the in each case 
being, of course, unknown. Far too little has as 

yet been done on the of form*, 

and it would be riwh to make as to the 

nature of the intermediates until the method of itx fieri- 
mental breeding has more employed 

in analysing their constitution, it Ii not 

without significance that the abundance or of 

the obawra form runs parallel with the cir 

scarcity of the intermediate*. It that the 

intermediates are heterozygous in for 

which the typical obscura is and the 

fact that the intermediates ar than 



x] MIMICRY AND VARIATION 129 

obscura Is what is to be looked for in a population mating 
at random. This case of the polymorphic Pseudacraea 
eurytus is one of the greatest interest, but it would be 
hazardous to draw any far-reaching deductions from 
such facts as are known at present. When the genetics 
of the various typical forms and of the intermediates 
has been worked out it will be disappointing if it does 
not throw clear and important light on these problems 
of mimetic resemblance. 

As the result of modern experimental breeding 
work it is recognised that an intermediate form between 
two definite varieties may be so because it is hetero- 
zygous for a factor for which one variety is homozygous 
and which is lacking in the other because it has 
received from only one parent what the two typical 
varieties receive from both parents or from neither. 
Its germ cells, however, are such as are produced by 
the two typical forms, and the intermediate cannot be 
regarded as a stage in the evolution of one variety from 
the other. In these cases of mimicry the existence of 
intermediate forms does not entail the deduction that 
they have played a part in the evolution of one pattern 
feom another under the influence of a given model. 
It is quite possible that the new mimetic pattern 
appeared suddenly as a sport and that the intermediates 
arose when, the new form bred with that which was 
already in existence. But before we are acquainted 
with the genetic relationships between the various 
forms, both types and intermediates, speculation as to 
their origin must remain comparatively worthless. 

P.M. 9 



130 



[OH, 



In this connection a few words on another source 
of variation may not b& out of place. The pat-term of 
butterflies are often very sensitive to changes* in the 
conditions to which they are exposed during later 
larval and pupal life. Many nmthn and buttctrilicH in 
temperate climates are double brooded. The laid 
by the late summer brood hatch out, hibernate in the 
larval or pupal state, and merge in this following 
spring. This spring brood produces the Hutnmrr brood 
during the same year. In thene it often hap]x*nH 

that the two broods differ in apjiearanw front one 
another, a phenomenon to which the* term "Seasonal 
Dimorphism " has been applied. A well-marked iiwtmiee 
is that of the little European VanaHHid, Anvtc.hnia 
levana. Tho so-called levana form which emerges in 
the spring is a small black and orange-brown butterfly 
(PL VI, fig. 10). From the laid by thin brood 

is produced another brood which latc*r on in 

the summer, and is, from its very different appearance, 
distinguished m the prortta form (PL VI, fig. 9). 
It is very much darker than, the spring form and in 
characterised by white bands the The 

eggs laid by the prorm form give rite to the 
form which in the following gpring. It has 

been shewn by various workers, more 
by the extensive experiments of Merrifield 1 , that the 
appearance of the levana or the form from any 

batch of eggs, whether laid by or is 

dependant upon the condition* of under 

/ mgr, /nttrnat. (PEntom.* 1011, 



x] MIMICRY AND VARIATION 

which the later larval and early pupal stages are passed. 
By cooling appropriately at the right stage levana can 
be made to produce levana instead of the prorsa which 
it normally produces under summer conditions. So 
also by appropriate warming prorsa will give rise to 
prorsa. Moreover, if the conditions are properly ad- 
justed an intermediate form porima can be produced, 
a form which occurs occasionally under natural con- 
ditions. The pattern is, in short, a function of the 
temperature to which certain earlier sensitive stages 
in this species are submitted. What is true of A. levana 
is true also of a number of other species. In some 
cases temperature is the factor that induces the vari- 
ation. In other countries where the year is marked 
by wet and dry seasons instead of warm and cold ones 
moisture is the agent that brings about the change. 
In some of the South African butterflies of the genus 
Precis the seasonal change may be even more con- 
spicuous than in A. levana. In Precis octavia, for 
example, the ground colour of the wet season form is 
predominantly red, while in the dry season form of 
the 3ame species the pattern is different, blue being 
the predominating colour (of. PL VI, figs. 11 and 12). 
Such examples as these are sufficient to shew how 
sensitive many butterflies are to changes in the con- 
ditions of later larval and earlier pupal life. The 
variations brought about in this way are as a rule 
smaller than in the examples chosen, but in no case 
are they known to be inherited, and in no case conse- 
quently could variation of this nature play any part in 

92 



132 



MIMICRY AND VARIATION 



[CH. 



evolutionary change. Before any given variation can 
be claimed as a possible stage in the development 
of a mimetic likeness satisfactory evidence must be 
forthcoming that it is not of this nature, but that it 
is transmissible and independent of climatic and 
other conditions. 

Many species of butterflies, especially such as are 
found over a wide range, exhibit minor varieties which 
are characteristic of given localities. These minor 
varieties may be quite small In Danaia chryttippu*, 
for example, African and Asiatic specimens can gener- 
ally be distinguished. On examples from India a 
small spot is seen just below the bar on the fora wing 
and on the inner side of it* Eastwards towards China 
this spot tends to become larger and confluent with 
the white bar, giving rise to an L~shaped marking; 
westwards in Africa the spot tends to disappear al- 
together. The existence of such local hm been 
used as an argument for the hereditary trannmisfuon of 
very small variationsin the present instance the size 
of a small white spot 1 . For if it can b supposed that 
small differences of this nature are always transmitted, 
it becomes less difficult to imagine that a mimetic 
resemblance has been brought about by a long 
of very small steps. But before this can be 
it is necessary to shew by experiment that the size 
of this spot is independent of environmental condition*, 
both climatic and other. Apart from and 
moisture it is not improbable that the formation of 

* 0*. Poulton, 5b0efc, Get. 1018, p. 300, 



MIMICRY AND VARIATION 



133 



pigment in the wings may depend in some degree upon 
the nature of the food. The larvae of D. chrysippus 
feed upon various Asclepiads, and it is at any rate 
conceivable that the pigment formation, and con- 
sequently the details of pattern, may be in slight 
measure affected by the plant species upon which they 
have fed. The species of food plants are more likely 
to be different at the extremities of the range of a 
widely distributed form like D, chrysippus, and if they 
are really a factor in the pattern it is at the extremities 
that we should expect to find the most distinct forms 1 . 
Actually we do find this in D. chryaippua, though it 
does not, of course, follow that the cause suggested is 
the true one, or, if true, the only one. Of the nature 
of local races too little at present is known to enable 
us to lay down any generalization. We must first 
learn by experiment how far they remain constant 
when transported from their own environment and 
bred in the environment under which another distinct 
local race is living. The behaviour of the transported 
race under the 1 altered conditions would help us in 
deciding whether any variation by which it is character- 
ised had a definite hereditary basis or was merely a 
fluctuation dependent upon something in the conditions 
under which it had grown up. The decision as to 
whether it is hereditary or not must depend upon, the 

1 The size of the white spot may shew much variation, in specimens 
from the same region. I have seen African specimens in which it is 
large, while in the Ceylon specimen figured on Plate IV it is as small as 
in the typical African specimen shewn on Plate VIII. 



134 



[on- 



test of breeding, through which alone we can hope to 
arrive at a satisfactory verdict upon any given 

The particular geographical variation which has 
just been considered happens to be a small one. But it 
may happen that a geographical variety ia much more 
distinct. Indeed it is not impossible that butterflies 
which are at present ranked a* distinct may 

prove eventually to be different forma of tho 
species. Especially is this likely to bo trua of many 
forms in South America, of which long ago 

remarked "that the suspicion of many of the* 
being nothing more than local modification!* of other 
forms has proved to be well founded/* Hinea 
day more material has been forthcoming 1 and it 
been shewn that certain colour schemim are character* 
istic of distinct geographical regions in Kouth America 
where they may occur in belonging to very 

different genera and families. In Central America, for 
example, the pattern common to many is 

mined by horizontal and oblique black on a bright 

fulvous brown ground, with two broken yallow 
towards the tip of the for wing. The type is 

well shewn by Medhanilis and the of 

DismorpMa praxinoe (PL X, 7 and 3). 
to this pattern gproup are a number of 

** *** * Jk 

belonging to various families, including Hell- 

conines and Ithomiines, Fiends such as 

and Perrhybrie, Nymphalines of the and 



Se Moulton, J, 0., ZVtm. Jfttf. SM. Lm^rn, 



MIMICRY AND VARIATION 



135 



Protogonim, and other forms. In Eastern Brazil the 
predominant pattern is one characterised by a yellow 
band across the hind wing and a white or yellow apical 
fore wing marking (of. PL XV, figs. 3 and 8). Here 
also, with the exception of the Perrhybris, all the 
various genera which figured in the last group are again 
represented. It is true that the members of this 
second group are regarded as belonging to different 
species from those of the first group, but as species 
here are made by the systematist chiefly, if not entirely, 
on the colour pattern this fact may not mean much. 
Passing now to Ega on the Upper Amazons the general 
ground colour is a deep chestnut purple and the apical 
area of the fore wings presents a much mottled appear- 
ance (of. PL XV, figs. 4 and 9). In this group again 
we find represented the different genera found in the 
other groups, the only notable absentees being JSresia 
and Perrhybria. Lastly in Ecuador, Peru, and Bolivia 
the general pattern scheme consists of orange-taway 
marMngs on a black ground (of. PL XV, figs. 5 and 10). 
This group differs somewhat in composition from the 
preceding in that it contains no Pierid and no Danaid. 
On the other hand its numbers have been strengthened 
by the accession of a PapiUo, an Acraea, and two 
species of the Satyrid genus PedaUodes. Certain writers 
have seen in the theory of mimicry the only explanation 
of these peculiar geographical pattern groups. The 
fashion is in each case set by the most abundant form, 
generally an Ithonmne of the genus Melinaea, The rest 
are mimics of this dominant species, either in the 



136 



[Cli 



Batesian or Mtillerian sense. Batcsian mimics are such 
genera as Diamorpkia and Protogonius, to which there 
are no reasons for attributing disagreeables properties. 
Of the nature of Mtillerian mimics on the other hand are 
the various HeliconincH and I thorn tines which enter 
into the combination, In each case the whole assem* 
blage is a great "mimicry ring," of which the pattern 
is dictated by the Ithomiine that predominates in }x>int 
of numbers. It is, however, very doubtful whether 
this can be accepted aa a satisfactory explanation. The 
four groups which we have considered arc* all character- 
ised by a peculiar and distinctive coloration, atid in 
each case the pattern must on the theory of mimicry 
be regarded as a highly efficient warning pattwn. One 
or other of these patterns must doubtless be looked upon 
as the most primitive. If so the question at once 
arises as to why a distasteful gonua should change from 
one efficient warning pattern to another quite distinct 
one. If the newer pattern affords protection 

we should expect it to have and eventually to 

have ousted the older one. That it has not done m 
must probably be attributed to the old being 

as efficient as the new one. But if thii is BO we arc 
left without grounds for assuming the to 

been brought about by natural the 

agency of enemies to whom warning colours 
For natural selection can only bring about a 
that is beneficial to the we 

suppose the change on the part of the dominant 
to have been independent of natural by 




MIMICRY AND VARIATION 



137 



enemies, and due to some condition or set of conditions 
of which we are ignorant. It is not inconceivable 
that the new colour scheme was associated with some 
physiological peculiarity which was advantageous to 
the species in its altered surroundings. If so natural 
selection may have favoured the new variety, not 
because of its colour scheme, but owing to the under- 
lying physiological differences of which the pattern is 
but an outward sign. And if this could happen in one 
species there seems to be no reason why it should not 
happen in others. The weak point of the explanation 
on the mimicry hypothesis is that it offers no explana- 
tion of the change in the so-called dominant Ithomiine 
pattern as we pass from one region to another. What- 
ever the cause of this change may be there would 
appear to be nothing against it having also operated 
to produce similar changes in other unrelated species, 
in which case the mimicry hypothesis becomes super- 
fluous. It is not unlikely that the establishing of these 
new forms was due to natural selection. If they were 
associated with physiological peculiarities better adapted 
for their environment it is reasonable to suppose that 
natural selection would favour their persistence as 
opposed to the older type until the latter was elimi- 
nated. But such action on the part of natural selection 
is quite distinct from that postulated on the mimicry 
hypothesis. On the one view the colour itself is 
selected because it is of direct advantage to its possessor ; 
on the other view the colour pattern is associated with 
a certain physiological constitution which places the 



138 



MIMICRY AND VARIATION [en, x 



butterflies possessing It at an a* comjutred 

with the rest 1 . 

It is, nevertheless, powible that mimicry may have 
played some part in connection with entablifihing the 
new colour pattern in some of South American, 

species. For if the now pattern had become 
lished in the predominant and if 

some of the members of a palatable form (*.. Prfi> 
gonim) were to shew a variation similar to that already 
established in the distasteful spede*, and if further 
there be granted the existence of apjtropriate enemieft, 
then it would be almost certain that the newer form in 
palatable species would eventually the older 

form. In such a the played by 

selection would be the preservation of a chance 
which happened to look like an form* 

There is no reason for regarding the a* 

%;a? %-,,^ 4E73S 

sar% brought about by the of 

a long of very small variations through the 

operation of natural 



1 In this oonafwtlcm it is of 
conaldtrftbi breeding experience 
variety of the Pppwd Moth In morn 
(of, p. 101), Th swift of the 

it MI better protested t bird 

that the deeper pigmentation is 
diffewaoe wMoh mtar for ^ntor 
qf Gmetim, vol. S, 1914. 



that the 

th typfan 
variety W to 

It in* htiwitvtif, 
with 



CHAPTER XI 

CONCLUSION 

the facts recorded in the preceding chapters 
it is clear that there are difficulties in the way of 
accepting the mimicry theory as an explanation of the 
remarkable resemblances which are often found between 
butterflies belonging to distinct groups. Of these 
difficulties two stand out beyond the rest, viz., the 
difficulty of finding the agent that shall exercise the 
appropriate powers of discrimination, and the difficulty 
of fitting in the theoretical process involving the in- 
cessant accumulation of minute variations with what 
is at present known of the facts of heredity. 

With regard to the former of these two difficulties 
we have seen that the supporters of the theory regard 
birds as the main selective agent. At the outset we 
are met with the fact that relatively few birds have been 
observed to prey habitually on butterflies, while some 
at any rate of those that do so shew no discrimination 
between what should be theoretically pleasant to eat 
and what should not be pleasant. Even if birds are 
the postulated enemies it must be further shewn 
that they exercise the postulated discrimination. It 
is required of them that they should do two things. 




140 



CONCLUSION 



CIL 



In the first place they must confuse an incipient or 
"rough" mimic with a modal sufficiently often to give 
it an advantage over those which have not varied in 
the direction of the model. In other wordu, they must 
be oaaily taken in. Secondly, they are exjeot.etl to 
bring about those marvellously clone resemblances that 
sometimes occur by confusing the exact mimicking 
pattern with the model* while at the name time elimin- 
ating those which vary ever BO little from it. In other 
words, they must be endowed with moat remarkably 
acute powers of discrimination. Clearly one cannot 
ask the same enemy to play both jmrte, If, therefore, 
birds help to bring about the reaemblahcc wt muxt 
suppose that it is done by different apecSoH that there 
are some which do the rough work, othent which do 
the smoothing, and others again which put on the final 
polish and keep it up to the mark. This in, of courae, 
a possibility, but before it can b aa a pro- 

bability some evidence must ba forthcoming in its 
favour. 

But even* if the difficulty of the appropriate 
be passed over, and it be that a 

resemblance can be built up through a number of 

* fe?^ 

separate steps, which have estab- 
lished through the agenoy of of birds 
with various but distinct discriminating we 
are left face to with an even more physio- 
logical difficulty. For why is it that when the end 
form which is supposed to have from this 
process is crossed back with the o; 



XI] 



CONCLUSION 



141 



the intermediate steps do not reappear? Why is it 
that when the altered germplasm is mingled with the 
original germplasm the various postulated stages be- 
tween them are not reformed ? For in various cases 
where we know the course of evolution this does occur. 
The pale pink sweet-pea has come from the wild purple 
by a series of definite steps, and when it is crossed back 
with the wild form the resulting plants give the series 
of stages that have occurred in the evolution of the 
pink. So also when the orange rabbit is crossed with 
'the wild grey form and the offspring are inbred there 
are reproduced the black, the tortoiseshell, and the 
chocolate, forms which are stages in the evolution of 
the orange from the wild grey. If then, to take an 
example, the "aristolochiae" form of Papilio polytes 
has been derived from the male-like form by a series 
of steps, why do we not get these steps reproduced 
after the germplasms of the two forms have been 
mingled? From the standpoint of modern genetic 
work the inference is that these postulated inter- 
mediate steps have never existed that the one form 
of pofytes female came directly from the other, and 
was not built up gradually through a series of stages 
by the selective agency of birds or any other dis- 
criminating enemy. 

These two objections, viz. the difficulty of finding 
the appropriate enemy, and the non-appearance of 
intermediates when the extreme forms are crossed, 
may, perhaps, be said to constitute the main objections 
to the current theory of mimicry. Others such as 



142 



[OH. 



the relative scarcity of mimicry in the male sex and the 
existence of cases of polymorphism among female* of 
a species which cannot possibly be explained on mimetic 
lines have already been mentioned. But while the 
main objections remain it is hardly necessary to insist 
upon those others. Looked at critically in the light 
of what w now know about heredity and variation the 
mimicry hypothesis is an unsatisfactory explanation of 
the way in which these remarkable resemhlancrH be- 
tween different species of butterflies have been brought 
about. Sometimes this is admitted by those who never- 
theless embrace the theory with a mild aloofness. 
For they argue that oven though it does not explain 
all the facts no other theory explains so many. Other* 
have sought an explanation in what has Hometimes 
been termed the hypothesis of external regarding 

these resemblances as brought about by similar con- 
ditions of soil and climate, and m forth. It is not 
inconceivable that certain ty|M> of colour and pattern 
may be the expression of deep-seated physiological 
differences, which place their at mi advan- 

tage as compared with the rest of the Wore 

this so it ia but reasonable to suppose they would 
become established through the of natural 

selection. But it is difficult, if not impossible, to 
this as a satisfactory solution, if for no other reason than 
that it offers no explanation of polymorphism. For 
example, each of the three forms of 
holds its own and aU must, therefore, be m 

equally well adapted to the circumstance* under which 






XI] 



CONCLUSION 



143 



they live. They are so distinct in colour that it is 
difficult on this hypothesis to suppose that they are 
all on the same footing in respect to their environment. 
Yet if one is better off than the others, how is it that 
these still exist? 

Those who have examined long series of these 
cases of resemblance among butterflies find it hard to 
believe that there is not some connection between 
them apart from climatic influence. One feels that 
they are too numerous and too striking to be all ex- 
plained away as mere coincidences engendered by like 
conditions. Nor is it improbable that natural selection 
in the form of the discriminating enemy may have 
played a part in connection with them, though a 
different one from that advocated on the current theory 
of mimicry. If we assume that sudden and readily 
appreciable variations of the nature of "sports" turn 
up from time to time, and if these variations happen to 
resemble a form protected by distastefulness so closely 
that the two can be confused by an enemy which has 
learned to avoid the latter, then there would appear 
to be good grounds for the mimicking sport becoming 
established as the type form of the species. For it 
has already been seen that a rare sport is not swamped 
by intercrossing with the normal form, but that on the 
contrary if it possess even a slight advantage, it must 
rapidly displace the form from which it sprang (cf. 
Chap. VIII). On this view natural selection in the form 
of the discriminating enemy will have played its part, 
but now with a difference. Instead of building up a 



CONCLUSION 




[OH. 



mimetic likeness bit by bit it will merely have eon- 
served and rendered numerically preponderant a like- 
ness which had turned up quite independently. The 
function of natural selection in respect of a mimetic 
likeness lies not in its formation but in ite conservation. 
It does not bring about the likeness, neither docB it 
accentuate it: it brings about the survival of those 
forms which happen to show the likeness. Why vari- 
ations on the part of one species should bmr a utrong 
resemblance to other, and often distantly related, 
species is another question altogether. 

Even a superficial survey of the fact** makoH it 
evident that oases of mimicry tend to run in Bftrien 
that a closely related series of mimic*, though often of 
very different pattern and colour, tends to ratmnble 
a closely related series of models. In Asia we have 
the Cosmodesmus Papilios mimicking a of 

fe iSM? 

Danaines, while the true Papilioe (of. Appendix 11) 
tend to resemble a series of tho less conspicuous mem- 
bers of the Pharmaoophagus group. In tho 
region the various species of Slymnicui form a 

resembling a series of Danauaefi. In Africa 
out the Cosmodesmus group again mimicking a Danaine 
series, and in part also an Acraaine Over- 

lapping the Aoraeines again ar various form* of the 
Nymphaline genus Pamdacram. It is also of 
that in Danais chrymppm and Acraea the 

Danaine and Acraeine overlap (of, PL IX). Similar 
phenomena occur also in South America, 
parallel series of colour patterns are exhibited 



XI] 



CONCLUSION 



145 



Ithomiines, by Heliconius, Lycarea, Dismorphia, and 
other genera ( of. p. 39) . On the other hand such mimetic 
resemblances as are shewn by the South American 
Swallow-tails of the Papilio and Cosmodesmus groups 
are almost all with the Pharmacophagus group, and 
almost all of the red-black kind (cf. p. 43). 

On the whole it may be stated that the majority 
of cases of mimicry fall into one or other of such series 
as the above. If we select a case of mimicry at random 
we shall generally find that there are at least several 
close allies of the mimic resembling several close allies 
of the model. Isolated cases such as the resemblance 
between Pareronia and Danais (p. 23), between 
Archonias and a Pharmacophagus Papilio (p. 43), or 
the extraordinary instance of Papilio laglaizei and 
AlcicUs agafhyrsus, must be regarded as exceptional. 

We have before us then a number of groups of 
butterflies each with a series of different colour patterns. 
In each group a portion of the series overlaps a portion 
of the series belonging to another more or less distantly 
related group. In the light of recent discoveries 
connected with heredity and variation the natural 
interpretation to such a set of phenomena would be 
somewhat as follows : Each group of Lepidoptera, such 
as those just discussed, contains, spread out among 
its various members, a number of hereditary factors 
for the determination of colour pattern. Within the 
group differences of pattern depend upon the presence 
or absence of this or that factor, the variety of pattern 
being the result of the many possible permutations and 



P. M. 



10 



146 



CONCLUSION 



[C1L 



combinations of these colour factors. Within 
limits of each group is found a definite number of these 
factors more in QUO group, leas in another. But some 
factors may bo common to two or more groups, in 
which case some of the permutations of the f tic tors 
would be similar in the, groups and would mwlt in 
identical or nearly identical pattern. To take*, a i triple 
example in illustration, let its fmppoRo that a given 
group, (a), contains the eight factor** A II, Sinoo 
any species in the group may exhibit any combination 
of one or more of these factors it follows that a con- 
siderable number of different forma are |KMwibio. Now 
suppose that another group, (0), distinguished from 
(a) by definite structural features, also contain* eight 
factors within the group, and that factor* are 

F -M, F t Q, and // being common to both (a) and 
($). Any combination therefor in (a)' lacking the 
factors <4 E will be paralleled by any combination in 
(/?) lacking the factors / Jf, For in both we 

should be dealing only with the F, Q, and H, 

which are common to group. So a third 

group might have some factors in common with (a) 
and some with ($)> and so on for other group*. In 
this way certain of the of colour found 

in (0) would overlap certain of in (a), while others 

of the groups (0) and (a) might overlap found in 

different groups again. The striking not 

infrequently found between belonging to quit 

distinct groups would on this view upon the 

hereditary factors for pattern and colour being limited 



XI] 



CONCLUSION 



147 



in number, so that the same assortment might not 
infrequently be brought together even though the 
group whose members exhibited the resemblance 
might, owing to structural differences, be placed in 
different families. 

We know from recent experimental work that 
something of the sort is to be found in the coat colours 
of different rodents. Agouti, black, chocolate, blue- 
agouti, blue, and fawn form a series of colours common 
to the rabbit, the mouse, and the guinea-pig. These 
colours are related to each other in the same way in 
these different beasts. In the rat, on the other hand, 
there occur of this range of colours only the agouti and 
the black. Each of these species again has certain 
colour patterns which are peculiar to itself, such as 
the "English" type in the rabbit, the tricolor pattern 
in the guinea-pig, or the "hooded" variety in the rat. 
The total range of colour and pattern is somewhat 
different for each species, but a few are common to 
them all. Moreover, there are others which are com- 
mon to the mouse and the rabbit but are not found 
in the guinea-pig, and others again which may occur 
in the rabbit and the guinea-pig but have not been 
met with in the other two. In certain features the 
rabbit might be said to "mimic" the mouse, and in 
other features the guinea-pig. It is not, of course, 
suggested that the case of the butterflies is so simple 
as that of the rodents, but so far as we can see at 
present there would seem to be no reason why the 
explanation should not be sought along the same lines. 

102 



148 




CONCLUSION 



[CH. 



On this view tho various colour patterns found among 
butterflies depend primarily upon definite hereditary 

factors of which tho number is by no means enormous, 
Many of these factors are common to several or many 
different groups, and a similar aggregate of colour 
factors, whether in an Ithomiine, a Pierid, or a Papilio, 
results in a similar colour seherae. The may 

be close without being exact because the total effect is 
dependent in some degree on the and relative 

frequency of the and other structural features, 

In so far as pattern Hypolimna* and 

Amauria echeria (PL VIII, 1 and 8} are exceed- 

ingly close. But inspection at once a difference 

in the quality of the scaling, giving to the Hypolimnae, 
where tho black and yellow meet, a or even 

raggedness of outline, which is distinct from the 
and more clear-out borders of the Amaurui. It in not 
unreasonable to suppose that carry 

A- * j$ 

identical factors for colour pattern, and that the 
differences by which the ye are 

dependent upon the minuter structural ueh 

as occur in the scaling. Bo the eye would 
between- a pattern printed in identical, colours on * 
piece of cretonne and a of Though 

pattern and colour were the the in 

material would yield a somewhat 

On the -view suggested the of mdmntio 

resemblances is the expression of the ooloor 

pattern is dependent upon 
of which the total number is by ao 



XI] 



CONCLUSION 



149 



As many of the factors are common to various groups 
of butterflies it is to be expected that certain of the 
colour patterns exhibited by one group should be 
paralleled by certain of those found in another group. 
That cases of resemblance should tend to run in parallel 
series in different groups is also to be expected, for 
in some groups the number of factors in common is 
likely to be greater than in other groups. In con- 
sonance with this view is the fact that where poly- 
morphism occurs among the females of a mimicking 
species the models, though often widely different in 
appearance, are, as a rule, closely related. Some of 
the Asiatic Papilios, for instance, resemble Danaines, 
while others resemble Pharmacophagus Papilios. But 
although the polymorphism exhibited by the females of 
a given species may be very marked, we do not find 
one of them resembling a Danaine and another a 
Pharmacophagus Swallow-tail. The models of a poly- 
morphic mimic are almost always closely related 
species 1 . 

In discussing the problems of mimicry more atten- 
tion is naturally paid to groups which exhibit the 
phenomenon than to those which either do not do so, 
or else only do so to a very limited extent. Yet the 
latter may be of considerable interest. Among the 
Pieridae of the Old World the phenomenon of mimicry 
is very rare. Pwreronia and Aporia agathon conform 



1 As examples may be mentioned P. polytes, HypoUnvnas iwisippus, 
H. dubiiui, and Pseudacraea hobleyi. With the exception of theplanemoides 
form it is true also for P. dwdanus, the most polymorphic of them alL 




CONCLUSION [CH. 

closely to the common Danaid typo reprtwnted by 
Danais wtf-garit* and other HpwicH, but apart from there 
none of the many PieridB in Asia rrsomblr any of the 
recognised models. Africa is apparently destitute of 
Pierids which mimic sppeics botanizing; to other groups. 
Yet no group of buttorfliw i iiior** j>oiwwi1{Kl by 
birds, Of all the instances of bird nitta-cks 
together by Marshall 1 more than otic-lliini an* i 
of attacks upon this group alone. If birds nro tho 
agents by which mimetic liken CHHOH AFP built- up thrt>ugh 
the cumulatiTD selection of mali variation^ how can 
the rarity or absence of mimetic Ptc*ridB in tho Old 
World be accounted for? For the | MHUC*^ of l*iorid, 
like the species of other famili&H, nlww tiouwilprabb 
variation, and if this proeeas of wetocstioni \vcrc? really 
at work one would xpoct to finci many more Picrid 
mimics in theao rogiona than actually occur. It ii 
true that the white, yellow, and rl pigments found 
in Pierids differ from those of othc*r btterflie in being 
composed either of uric aoici or of sornc Rtiimtance 
closely allied to that body f . Tlienc* are 

generally found "between tho two layers of ohitin, of 
which the scale is composed, pigment 

is intimately associated with thet ohitin of the 
itself. What is perhaps the factor in the 

formation of a mimetic distribution of 

the black pigment with to the lighter pig- 

ments; and although the latter distinct 

1 Trms, Jffnf. S. Lond. 11KH>. 

8 Of. F. O. HopMni, PMl Trm, May. Sot, 1895. 



r 



XI] 



CONCLUSION 



151 



in the Pierids as compared with other butterflies, there 
would seem to be no reason why the same factors 
governing the distribution of black should not be 
common to members of different groups. A distri- 
bution of black pigment similar to that found in a 
model and its mimic may occur also in a non-mimetic 
ally of the mimic. Dismorphia astynome, for example, 
resembles the Ithomiine Mechanics lysimnia (PL XV, 
fig. 8) both in the distribution of black as well as 
of yellow and bright brown pigments. A similar 
distribution of the black pigment is also found in 
Dismorphia, avonia, but the yellow and bright brown 
of the other two species is here replaced with white. 
By a slight though definite alteration in chemical 
composition this white pigment -could be changed into 
bright brown and yellow with the result that D. avonia 
would closely resemble D. astynome in its colour scheme 
and would in this way also become a mimic of Mecha- 
nitis lysimnia. Another good instance is that of the 
females of Perrhybris demopkile and P. lorena, the 
former being black and white, whereas in the latter 
the white is replaced by yellow and bright brown, 
giving the insect a typical Ithomiine appearance 1 . 
Here again a definite small change in the composition 
of the pigment laid down in the scales would result in 
the establishing of a mimetic likeness where there would 
otherwise be not even a suggestion of it. It is in 
accordance with what we know to-day of variation 

1 Colotired representations of these two species will be found on 
PI. 20 of Seitz, Macrolepidoptera of the World, Fawna Americana. 



152 



[OH, 



that such a change should appear suddenly, complete 
from the start. And if so there is no difficulty in sup- 
posing that it might bo of some advantage to its 
possessor through the resemblance to an unpalatable 
form. Even were the advantage* but a alight one it 
is clear from previous discussion (p. 96) that the* new 
variety would more or less rapidly replace tho form 
from which it had sprung. With the* continued 
operation of natural selection the now form would 
entirely supplant the original one*, but it is not im- 
possible that in some the mdmt-ing agent may IKS 
removed before this result has been achieved. In this 
event the proportions of the new and tho old form 
would fall into a condition of equilibrium it in P. 
polytea in Coy Ion, until Homo other Helective agent 
arose to disturb the balance. On this view natural 
selection is a real factor in connection with mimicry, 
but its function is to conserve and render preponderant 
an already existing likeness, not to build up that like- 
ness through the accumulation of small variations, as 
is so generally assumed. Recent in heredity 
aad variation all point to this restriction of the 
of natural selection. Hitherto an argument in favour 
of the older view has been that derived from the study 
of adaptation of an apparent purpose, which, at 
sight, appears to be behind the manner in which 
animals fit into their surroundings* For many the 
explanation of this apparent purpose ha found 
in the process of natural selection operating gradually 
upon smaU variations, accumulating and rejecting 



CONCLUSION 



153 



others, working as it were upon a plastic organism, 
moulding it little by little to a more and more perfect 
adaptation to its surroundings. On this view adapta- 
tion is easy to understand. The simplicity of the 
explanation is in itself attractive. But when the 
facts come to be examined critically it is evident that 
there are grave, if not insuperable, difficulties in the way 
of its acceptance. To outline some of these has been 
the object of the present essay. Though suggestions 
have been made as to the lines along which an ex- 
planation may eventually be sought it is not pre- 
tended that the evidence is yet strong enough to 
justify more than suggestions. Few cases of mimicry 
have as yet been studied in any detail, and until this 
has been done many of the points at issue must remain 
undecided. Nevertheless, the facts, so far as we at 
present know them, tell definitely against the views 
generally held as to the part played by natural selection 
in the process of evolution. 




FOR the table on p. 155 I am indebted to the? kindncwt of 
Mr H. T, J. Norton of Trinity College*, Cambridge, It afford* 
an easy means of estimating the ehangn brought About through 
selection with regard to a given hereditary factor in a population 
of mixed nature mating at random. It must bo rappowd that 
the character depending upon the given factor hew nomptato 
dominance, so that there is no visible distinction between the 
homossygoua and the heterozygous forms. The thmt HttH of 
figures in the left-hand column indicate different pottiticmH of 
equilibrium in a population consisting of homoaiygous domi- 
nants, heterozygous dominants, And rocofwiveii. The remaining 
columns indicate the number of generations in which ft popu- 
lation will para from one position of equilibrium U> another, 
under a given intensity of selection, The intensity of Httlwtion 
is indicated by the fractions J$f*, A$, etc. Thu Vf meann 
that where the ohancon of the favoured new variety of iturviving 
to produce offspring arc 100, those of the older variety against 
which selection is operating are aa 75 ; there in a 2S % iwloction 
rate in favour of the new form. 

The working of the table may perhaps be best explained by 
a couple of simple examples, 

In a population in equilibrium conninting of homozygotui 
dominants, heterozygous dominants and the last 

named olaas comprises 2*8 % of the total : amuming that ft 
10 % selection rat now operates in its favour M opponod to 
the two Glasses of dominants -in how many gonerationfi will 

W ? 

the recessive come to constitute one-quarter of the population ? 
The answer is to be looked for in column B the favoured 

variety is recessive) under the fraction jyjp. The 




ORIENTAL BUTTBRKLIK8 



1. Pomwta ceylonica 
2, 

4, Paptlio xmadm 

5, HypoKmna* boUna $ 

7. Papilio dytia var, 

8. i var, tankmwam 
8. Mtymnw ringbala 

10, JPwptoiw 



1 

\ (P 

J 




10 



ORIENTAL BUTTERFLIES 




PLATE II 

ORIENTAL BUTTEHFLIKH 

L Delia* mteharitt 

2. Caduga tytfa 

3, Papilio agtstor 

4, fSupfaea mul&iber 

5. it i 

0. IStymniag maMtu 
7. M ,, 



(Papilttmuiru< 
(I>naini>) 

(Biityrini) 



8. Kuphea rhadamanthm (Danaituut) 

0. PapUw mmd&x (Pttpilianttla) 




ORIENTAL BUTTERFLIES 




PLATE III 

ORIENTAL MOTHS AND lU'TTKHFUKB 

Tho three uppw figure* are thcn of motlw, imd tho thrw lower 

ones two thorn of oufctarfliw, 



1. Alcidis ayathyrmui (Ni*w Cluiit*a) 

2. Papilla taglaiwi 

Tho moth in horo KuppOHod to serve an ft modt*} for th fw 
Papilio, 

3. Cyclottia htuttiniaide* 

4. tdeojma daa$ 

Tho butterfly in vi*ry common and muMt be Kigiwtlwl tut the model, 
the rtwror moth HH tho mimic. 



R. Epi^Qpela potydktm (Amm) 
0, Papilio bootM 

Both of thwi im-Kiitw ar< to ba mgardtwi wi rrtimiw of the 
Pharroooophnguit Fapiito, /*, palyxenuti, whioh in vnry like I** Jkwfet in 



PLATE IV 
ORIENTAL BUTTKBFLIE8 



R , . _ 

2. jjteappw 9 

3. Argynnw hyperMm 



(Nymphaltnao) 



. Slymnias undularut 



7, HypoUmnm mMppm 
8. 



The two Danaldn tognthor with the fettwi3J of ihe other 

im form a M mimicry riag, n For dxpiwtJft mm text, pp. 




J'lutr IV 




ORIENTAL BUTTERFLIES 



PLATE V 
ORIENTAL BUTTKRFUKH 



vw t^riMr (Af form) 
, vr. ptyw (A form) 

V vgyr, rornutw (H form) 



Tho Bpooirnottfl fiffuw>d on tWi ptfttf 
tboy are aJi plentiful. 

la-6a rwpri*nfc tt uadtr 
to aptjoitnonif 



tnJk in Coyloa where 
of the hind wingtt 




Ifl 




ORIENT A 1 , B UTTE RFLIES 




PLATE VI 

AFEICAN BUTTRKKURH 
(except A, fomna, Fig*. 8-10, whirl* in Kiirapcn) 

1. IMnait petivtntna (Dwnunw) 

2, JF'ajrfKo tmnidm (l*ft|iltfni<iiu<) 

3. ^twattfij h^itm (Dftitiiu) 

4, Papilio leonideut var, (l'jUimdtt) 
0, FMtufocraea bm^tmli (NymphlinM) 



7, Acfaea eyifm (AaitMtiniws) 

8. ArtHtchnia fewm* var, porima 

i, vwr, jomfiW 

JO, n 

11, Precis odama vw, 

12. var. natabtnri* 



Plain VI 




11 



12 



AFRICAN BUTTERFLIES 




PLATE VII 

TROPICAL AFRICAN BUTTKRPLIKH 

1. Plamtma maaaritla d (AeriwnniM*) 

2. f 

3. , (Mm 

4, n jmragm t 

5, tl epa^a M 

6, PMudaora&t hobfoyi ^ (Nymphftlm) 

7 o 

/. H n * f 

8. n tfffd i> 

0. JSlymnia* pheffta 9 (Btyrinin) 
10. Papilto aymrta f (X*piUonidaa) 

, Pmtdaram faefotefi and P. torro (Fiw, 6-^) wew* at 
timb regarded an wtpmnite pi, More raoimUy they haw been 

fco be forms of the poIymorpWe mrytwt.) 



x h 



II 





10 



TROPICAL AFRICAN BUTTERFLIES 




PLATE VIII 

AFRICAN BUTTKtlFUEH 
I, Papilla dardanug $ 



5, vr. 
9 vw. 
9 vr. 



3. 



5, Danai* ckryijtjnu 

0. Xtnaurur nmvim ,, 

7, , echeria 

8* Hypalimntu dubiut var, mima (NymphiUinM) 




i in 




AFRICAN BUTTERFLIES 



I'tnlr. /A' 




Dunn in c/i nj 
n. Typical form 



I )t 



form 
form 



Acraea cncedon 
cl. Typical, form 
o. Alcippina form 
f. Daira form 



Hypolimnas misippus <j? 
g. Typical forin 
h. Alcippoides form 
i. Inaria form 

(After Aurivillrus) 




PLATE X 

SOUTH AMERICAN BUTTKHFLIKB 



1. Dimwrphia eretatra c | 

2, praxmm <jf 

3, , ? 

4. Perrhybris tnalenka $ 

0. 

7, MKchanUi mtturata 

8. V a pil fa zagrew 

0, rrotoyoniu* tithweidtu 

3 0, Tilhorea 



Tht fiffun of the* Mrehantti* (Fig, 7) w Uvkt*n fm ft mtbw 

worn Hptieirnttn, Tfi (junlitv of the* oriwigt* hrcwrt s t.*tt**t hew by 
thi p!JKHn illiwtml^tl in Fig, 7 tin Plato XV.) 




10 



SOUTH AMERICAN BUTTERFLIES 



L Haftoontot ndpfvurta {HHrK>niniM) 

2, Papitia paumnmtt 

3. 

4, Oateni tektipfa 

5, MiUoomm mdjmmm (Holionin) 

6, Pem4 ^hofffpa 9 (Piridiu) 
7 M ^ 

8, Fojpaio 

8. t 

10, 




Plate XI 




1O 



SOUTH AMERICAN BUTTERFLIES 



A n 




SOUTH AMERICAN BUTTERFLIES 



Plata XIII 




MODELS 

1. Papilio nephalion 

2. ,, c/iamissonia 
(\. ,, perrhebus 



MIMICS 

4. Papilio lysithous var. lysithous 

5. ,, ,, var. rurik 

(5. ,, ,, var. pomponius 



(For further details of this case see Jordan, I'"' Congr. Internat. 
d'Enlomologie, Bruxelles, 1911, p. 396.) 




1. McJlttinn cunfnxti, !H> 
( J( lutuiiiiuu 1 ) 




iitri<hiti ni*t't\ ' |*i 
( I'ii'rtttut 1 ) 



., f \ ^"' , 

V. .-r- ' "' **, J r- v * V 

> ,;." v \ - w< .." W, 




" %^,r 



,'}. Tlit/ridia theminlo, x 00 




* I .4." Ai 4 I 




4. Ilunailione, x90 5. CasLnia sp., xflO 

(I)anainiio) (Moth) 

MierophotographB of tho scales of various Lopidoptera in the S. American 
" TraiiHparoncy group." For explanation see text, pp. 39-42. 




PLATE XV 
CENTRAL AND HOUTH AMERICAN BUTTERFLIES 

HlufttfftUng th dowdy jMimitd Rrdwi of pultonm occurring in the 
two dutinut group H^Iiotnunao ttl Ithomiiuft 

1, HeKctmim mirwt 

2, 

3, 



pardalinu* 



6. MichanUis dim 

1, 

8, lymmnm 



Plata XV 




10 



CENTRAL AND SOUTH! AMERICAN BUTTERFLIES 




PLATE XVI 

NORTH AMERICAN BUTTERFLIES 

1, Papilw philtnor 

2, tm4ku 

3, ArgynnUt dta,na, 9 
4, 

8. >. 

fi. arcMpput 

7, , fturidtsntii 

i arfhippu* 



x 3 



Watt A' IV 




NORTH AMERICAN BUTTERFLIES 



INDEX 



References to th& plates are given m thicker type 



, taken by kestrel, 118; 
A. aosina, 122; A, ca'tdarena, 
122; A. egma, 34, VI. 7; 
A. eneeefon, patterns of dif- 
ferent forms in relation to 
those of Demons ch/rysyppus, 29, 
144; typical form of, IX. d; 
altippina form of, IX. e ; daira 
form of, IX. f ; A. halaU, 122; 
A. violae, 33 note; eaton by 
lizards, 108; attacked by birds, 
110, 117 

Acraeinae, as models for African 
butterflies, 33 

Adaptation and Natural Selection, 
61 

Adclpha, 54 

African butterflies, mimicry 
among, 28-30 

Aloidis agathyfsua, 27, 146, EGT. 1 

A Mia h&loiUi, 38 

Amauria echeria, 30, 148, VUL 7; 
A. hyalites, 30, VI. 2; A. 
niaviiM> 30, VJH. 6 

Amphidasys betid&ria, rapidity of 
increase in melanie sport of, 
101 

Anosia pl&vippw (I)anaw ar< 
ohippua), 113 

Antfiomym, 41 

Aporia agathon, 140 

Araschnia l&vana, Beasonal dimor" 
phiain in, 130; typical form, 
vX 10; prorsa form, VI. 9; 
porvma form, VI. 8 

Archonias, 43, 58, 146; A, onfios, 
XI. 10 



Argywws diana, 47, XVI. 8? 
A. hyperbms, 29; as mimio 
of Danais pl&xippits, 52; in 
mimicry ring, 66, IV. 8, 4 

Artamw^ fua<yus, 112 

Asilid flies, as enemies of butter- 
flies, 106 

Athyma punctata, 63 

Bates, G. L., on contents of birds' 
stomachs, 118 

Bates, H. W., on mimicry, 9j on 
resemblances between, unpalat- 
ablo forms, 14; on initial 
variation in mimetio resem- 
blance, 08 ; on 8. American 
Berines attacked by birds, 112 

Bateson, 3 

Mct.cnoiH, 36 

Bingharn, on birds eating butter* 
flies, 110 

Birds, as enemies of butterflies, 
100; stomach contents of, 
113; feeding experiments with, 
116; colour perception in, 119 

Bowater, on Amphidasys bePularia, 
102, 137 not 

Breeding experiments, with Hypo- 
Utrmas dww,80 ; with PapiUo 
polyt&s, 84 ; with PapiUo m&m- 
non, 89 ; with PcvpiUo dcerdanua, 
90 ; with Ps&uda&r aea &im/tU8, 
128 

Bryant, on birds eating butter- 
flies, 114 

'Buchanga atra, 111 

BybUa Uithyia, 122 



184 



INDEX 



24. M. H. 



t>rwin, nn tmtuml wlwtton, I ; 
rot lulfttntiuu. fi; m initial 

m 
of 



, 

I'urt t.**r, ' if*r **!**'* in tttn mimicry fhr>\ fill 

I",/- ?i ' mi 5- ;/ffM, 12*4, *n fMfttce in tilf**rtlt 
l-v, <. ut -* rm* MM iill rwilA^lw* ftH; 

t, HA, n, n. 

Md|.*w, cm br 

< .r f, 41, E I 8 

>.;* i^ii * in i iii v 3 

* v* "*** *^ 

l*, It*; f*. miittim, 

it* 



f 



f <*> # iA#'W* fit 

f hw nr* 11*1 



t **f I* ft 

*fr%# 

***># 



IM 

$ 






t*| 



of 



of mnny forttw, 



its 



,._.-Un*a w*th i !*' of 

14ft; /A tuiynomft 

*^ * **. + ?t 

t/ atx$fff l** ; // 

"' a Hf T 1 /I ttriir 

> W* * Jkt *,.** !"''* > 



c4 Mi 
^ M of, Si 



* /* ^fW '**', * 

, * 1, X. i, 8; 
trf ftiitnirry nji 134 



If not**, 42 not**, 



. in *'WW rtfn 

f Uiutmtitu*. 
ifelti*. 24, n. i 
;, 3ft, VH.9: 
>, I. 9i &*. uiKlii. 

;, Oil, US 



* V "* T *** 

*47, in. a 

* s u J 

" iuit 1 



SS IOH. U. US. 

, 24, 81, 
t 24, 



"f, ^- ; 
IWUT. 



IS it* 



INDEX 185 



Euripua 



, 24 



Feeding experiments, with Man- 

tids, 105; with lizards, 107 

with birds, 115; W ith mam- 

mala, 121 
Finn, on feeding experiments with 

liBarda, 108; on foeding eacperf. 

mentB with Indian birds, IIS; 

on feeding experiments with a 

Trae-shrow, 121 
Plight, different in model and 

mimic, 55; difference of in 

/ aputo polyim and its models, 

0*1 

Fryer, on breeding Papilio polyt0 9> 

84; on relative abundance of 

females of PapiUo poises in 

Ceylon, 07; on birds eating 

unpalatable" butterflies, 112 

O&trhonotw infernalis, 108 

Haase, on mimicry, 10; on olasai- 

fioation of Papilionidae, 25 
Hahnel, on S. American Pierinoa 

attacked by birds, 1.12 
Hardy, on conditions of equili- 

brium in a mixed population, 

94 

He< ?l f ' n birdl1 ^^S butterflies, 

Hebomoia, HO 

HeHeonina, a models for 8. 
American butterflies, 88 

Hehconius, 146; f. worote, XV, 8; 
H. mdpomene, as model, 42. 
4J, XI. 6 ; H. mints, XV- 1 ; 
//. pardaUnus, XV. 4 ; // 
spfaulena, XV. 5 ; /f . aulphurea, 
4.3, XI. 1; j^. telchinia, XV. 2; 
//. telesiphe, XI. 3 

Herpestes gahra, 121 

Ht)H, on colour porooption in 
birdH, 119 

Hopldpa, on pigment of Pieridn, 150 

ayjMlmnae dttbius, polymorphism 
S' 22i ** rnimio J >anainei, 
oO, VII. 8, 9 ; breeding experi- 
ments with, SO; var. mima 



with model, 148; 
patterns of in relation to 



117, I. 5, 6? H. , , 

20, as model, 63; flight of, 
05; uxmlmiocy ring, 66, 110; 
eaten by Brown Shrike, 117; 
aMppoides form, EK. hi t 

IV '7' 8^ 1{ 



Initial variation, difficulty of, 03 

Insect enemies of butterflies, 105 

Intermediates, between different 

forma of Pmudtwraoa eivrytua, 

Jon' * n r I afc ton to mimicry, 

129, 140 

Ithomiinao, oharaoteriatioa of, 10: 
as xnodete for S. American 
butterflies, 38 

Ituna, 30 ; /. itiane, 40, XIV. 4 
/. phetiarele, XH, 8 

Jaoobmm, experiments with Fa- 

piMo mmnnon, 89 
Jordan, 40 note 
Junonia, 111 



t 117 

atbomaoulata, 53; L. 
ts, 40, gg, XVI. 0; 

L. (mhwvia, 47, 49, XVI. 4; 

L. ostyanaas, 47, XVt. 6 ; L. 

flpridmma (moroa), 49, XVI. 7- 

L. proserpina, 47 ' 

Idzarda, as onemiee of butterflies, 

107 
Local varieties, in connection 

with mimicry, 182 
Lyoaenidae, as mimics in Africa, 35 
Lycorea, 146 

MfeAtoe, on feeding experiments 

with birds, 118 
Mammals, as enemies of butter- 

flies, 121 
Mandera, on feeding eam 

yjth Itearda, 10f; ^ft 




40, XIV. i f). 




Caduffa ifia, 24. 61, It 
Cattametna pieridoidej, 5ft 
Gcdotm (^phiomadiita, 107 ; C. vern~ 

eofor, 107 

Carpenter, on intcrmodiattw in 
rtttwdacraea eurytu*, 120; on 
bwHKling experiments with 
'acram turyiwt, 128 
OH mimic, 39, XH. 4; 
of, 41, XV. S 

.,. , 121; 6 f , floretta, 111; 

{"'. pyranthe, 111 
CwcAttei* Tupwxtl&idM, 118; C. 
naumanm, 117 

pygerythrm, 121 
CVwraw ftem* 110 
OUrtmaphila mmiU* 36 
Cljywfi'oatkm of butterfliw 18-21 
Coiaefti* teiwripJte, 38, XX* 4 
Cydotfa hmtinioulmt 131. 8 
Cymat&phara or, tteblhmftt of 

melsyiio HTwrfc in 10S notn 
yrmt/i <%0aama#, 110 

..., ohawusteristiefl of, 12 1 
ttuxlelM for Oriental butter- 
mi model** for Africnn 
Isutttirflifw, 28 

Danai*, HI, 145; /->. archippwi> 
48; ettt<*n by lixttrd, 108; 
mjwtxHl by bird, 113. XVI. 8; 
/>, tmmnice* 48, XVI % 0; /->. 
efvrytipfnt*, 23, 28; flight of, 
65 j in Hiimfory ring, 65 ; otifcm 
by lieArdfi, 108 s mtn by Ii 
efttf*r 111} iittten by Brown 
Bluito, 1 17 1 rtijttotucf by Ki- 
tnd, 118; rejected by tabcxm, 
1$2| loeal vaxiation in, 13%; 
pftttwnw overlapping with those 
of A&raea mmmm^ 144 ; atrip- 
mm form, IX. to ; dtmmwt 
Ibnn, IX. C; typicml fonn, 
W. 1 VIH. 5# D. pl6xipput 
m model for Argynni* hyper" 
Mwt , 62 ; In inteuory ring, 5 ; 
eaten by Liothrix, 118 note, 
,2fl,VLlt 



Darwin, on natural Relation, 1 ; 
on adaptation, 5; on initial 
variation in inimetic r0.Hcrn- 
blanoe, 03; on a difficulty of 
tho mimicry theory, 05 
e in buttt^rfli<H, 54 
m*/M*ro, 50; /->. cucAorw, 
28, 11 6 f llfl, H.I 

do Meijew, on bre<*ding I*apilio 
itwmnon, 80 

cl.* VrinH, 3 

Diimwrjthia, a mtrnirrt of Itho- 
ntiimu*. 3K. 42; rt*trie.t<Hl 
rAngi* of many forrtw, 61 ; 
diversity of pnttwn in gn\WM, 
fi8 ; iw Bftt<wtwt futinicit, 135; 
tmtt*rnH pwftllel with thot of 
Ithoiminfus 145; />. 
151; D. atxmta, 18 1 
crefritftia, fit H, 02 k X. 1 />. 
as mimia, 3B, XII. 2 ; 



/>. 



t>f , 



i ). imMniHi, w 
mimic. 67, 62. X. 2,3; w 
nu.tmbfr of mimiery rittg, 134 



of, fi5 

Ettringlmm, 17 not**, 33 note, 

com- 



t 8 ; D. mlffttrii, 150 



; piittornii m , 
with thcuttt of I! 

h, 144; ^. makla*, 24, n. 6, 

7 ; A\ jih&jMt, 35, Til. ; 

j. tmyhakt, 25, I. 9j &'. umi*- 

tori, tn mimierv ring, Oft, 115 

note, 11 , XV* 0,6 

fH%fora ( 27, JH. 6 
Bqwiltbrium, eoKidltiorw of irt 

mixod iwpulttticm, 03 
l?wfi 134, 135 
i/ufftmia eoli/amfco, 114 
JSuiphaeaim nutftina, 30 
Xuptoeet cow, 26, 108, 110, 112, 

tlO. j. m4t*&cr, 24, 61, 

II. 4. 5* &' rhaflattmnihm, 24, 
r>l, II, 8; JB. tafflmU, 110 

Euplottiiuu), chttract*riticai of, 22 ; 
an roodeto lor Oriental butter- 
flieM, 24 j in relittmn to bird*, 

III, US, H6 note 



INDEX 



185 



ffluripw 



, 24 



Feeding experiments, with Man- 
tida, 105; with lizards, 107; 
with birds, 116; with mam- 
mals, 121 

Finn, on feeding experiments with 
lizards, 108; on feeding experi- 
ments with Indian birds, 116; 
on feeding experiments with a 
Tree-shrew, 121 

Flight, different in model and 
mimic, 55; difference of in 
Paptti& polyps and its models, 
82 

Fryer, on breeding Papilio polytes, 
84; on relative abundance of 
females of Papilio polytes in 
Ceylon, 97; on birds eating 
"unpalatable'* butterflies, 112 



inf&rnalis, 108 



Haase, on mimicry, 16 ; on classi- 

fication of Papilionidae, 25 
Hohnel, on 8. American Pierines 

attacked by birds, 112 
Hardy, on conditions of equili- 

brium in a mixed population, 

94 
Hearsy, on birds eating butterflies, 

HI 

Hebomoia, 110 
Heliooninae, as models for 8. 

American butterflies, 38 
Helieoniu$> 145 ; JET. euarate, XV. 8 ; 

H. mel/pomene, as model, 42, 

43, XI. 5 ; H. vmrua, XV. 1 ; 

H. pardaUmis, XV. 4; H. 

splendens, XV. 5 ; H. eulphurea, 

43, XI. 1; H. telohinia, XV. 2; 

H. telesiphe, XI. 3 
Herp&stes galera, 121 
Hess, on colour perception in 

birds, 110 

Hopkins, on pigment of Piorids, 150 
Hypolinmas dubius, polymorphism 

in, 30; as mimic of Danaines, 

30, VH. 8, 9 ; breeding experi- 

ments with, 80; var. nwma 



compared with model, 148; 
patterns of in relation to 
models, 149; H. boUna, 25, 
117, I. 5, 6; H. misipp/u*, 25, 
29, as model, 53; flight of, 
55; in mimicry rijog, 06, 116; 
eaten by Brown Shrike, 117; 
al&ippoides form, DL h; iuwna 
form, EK. i ; typical form, 
IV. 7, 8, IX. g 

Ideopns daoa, III. 4 
Initial variation, difficulty of, 63 
Insect enemies of butterflies, 105 
Intermediates, between different 

forms of Paeudaorcwi, eurytw, 

128; in relation to mimicry, 

129, 140 
Ithomiinae, characteristics of, 10; 

as models for S. American 

butterflies, 38 
. Ituna, 39 ; I. ilione, 40, XIV. 4 ; 

I. phenarete, XII. 8 

Jacobsen, experiments with Pa- 

piUo memnon, 89 
Jordan, 40 note 
Junonia, 111 

Lanius wistatus, 117 

Lvmenitis atttomaculata, 53; L. 

arcMppWi, 49, 59, XVI. 6; 

L. arifwms, 47, 49, XVI. 4 ; 

L. aatycmax, 47, XVI. 5; L. 

flondensia (=eroj), 49, XVI. 7; 

JD. proserpina, 47 
Lizards, as enemies of butterflies, 

107 
Local varieties, in connection 

with mimicrjr, 132 
Lycaenidae, as mimics in Africa, 35 
Lycoroa, 145 

McAtee, on feeding experiments 
with birds, 118 

Mammals, as enemies of butter- 
flies, 121 

Manders, on feeding experiments 
with lizards, 107 ; with birds, 
117 



186 



INDEX 



Mantida, as cmomicw of butterflies, 
105 

Marshall, on Mullcriftn mimicry, 
72j cm fcvding expwimwnt* 
with Mantidfi, lOfij on birds tm 
twunic'M of bufctwfliwj, 107; on 
fwding oxporimfnt* with 8. 
African birds* 117; with mon- 
keys, 121; on birdR attacking 
Pitflddft, ISO 

Merhaniim tigaewn*,, XV. 0; A/. 
tlitn, XV. 0; JW. tyttimnin t 151, 
XV. 8; Af. mrffama, XV. 10; 
<M, witornki, nw modnl for 
ttiimwrphia pnusinm, 87, 62; 
at* mranbor of mimicry ring* 
134, XV. 7 

M*l&nia port in mathit, 101 

Afoiinaea, 188 

MeKnda /0rmoj App, II 

Melittnphagwi me4,mtmi t 110 
'iff, 111 



130 
Methawt ctmfwta, XXL I XIV* 1 

Migratory birdn, tiggitd in- 
fliumpo cm mimicry of, S3 

Mima^ram> 35 

Mimcttio nwcufHblrwiWj AM induced 
through gr&dtml ulighfc ahang^t, 
64 

Mimio* oomipying mmm station us 
rnodl 51 1 cmotinying Ktatitm 
ttpart from model, 83 '{ wwwir 
than mcxlel, 66 j pattern of in 
relation to ftllins, 57 

Hiai6ry Wllo f i conditions of, 
&0| Batemaft, 9 1 Muilwifm, 14 
rtnp 8{ in 8. Amtrioia 
, 1B4| and 



Mittiiery tbeory, of, 180 



Mothi, mimioty in, 27, 38 
Moulton, on S* American mirniory 
^i, KM 
, 14, 72 

mimicry, 58, ^57/T 66 i 
difflmilties of, 72 



Mutation, we Sport 
Mylothrw, 36 

Natural naleotton and mimicry, 

10-12, 61, 92, 152 

NMU, on monkoy aft cmomiiw of 
buttvflii, 123 

Nephcrnnia, (--'/'areronia 
116 

imitajwi, 24; JV, 
54; A7, Jtamarujm*, 121 

North Amoriwtn butt^rflioa, mimi- 
cry among, 45 

Norton, on ritpidit.y of ahangt* 
in rnixl rvofnilationn through 
natnriU f4tion, i4 App. I 

OritmtiU bxtttrrfUf, mimiory 



Overlapping in pafcfcwrrw of dif- 
fwttnt group* of buttorflicM, 

144 

PapUio arbtofochian, m model for 

female of P. p&lytM, 18, 20, 
52, 77 { rung** of, 70 j likm*M 
to P. polyta*, 80 $ character- 

of, '81; flight of, 82? 
eaten by lieardu, lw$i rejiwted 
by rtftin birdii, 115, 116} 
diftHkod by Tr*-ihrow, 121, 
V. 6, 6 a; P. o0m(or, 24, 51, 

fcarAtw, App. II j P, frocNto, 27, 
HI, j P. bm4dm t Si, VI. 4 j 
P, efasmiMonta, 44, XX0, 2| 

P. elyli'a, 28, 15, 60, 1.7,8? 
P, com, 20, 89 1 P. cpwto, 85, 
86, VH, 10 { P. darAwtw, in- 
vwrtlAtfd by Triman, 14 1 

mirowey in, 80? briliBg ex 
prfnait with, iOj poly- 
morphic format of in relation to 
modal*, 149 notoj yar, hum* 
bt&ti t 33; vftr, nwrwtwt t 32 j 
$ oenea, S I , VTO. 4 j 9 ditmj/mu, 
81, 88 1 $ h4mGom, 81, 
VIII. 8; $ nimmdw, S2, 33; 

fptmmnoMm, 31 5 9 
Sj $ en'mwtl, 81, 



INDEX 



187 



$ trophoniw, 31, 122, VHI. 
2; P. del&Gserti, App. II; 
P. 'demokua, 111, 121; P. 
ec^ertoidea, App. II; P. en- 
thonma, 110; P. &M&rpinu8) 
42, 43; P. gr&ntcua, 45; var. 
/fwnw, 46; P. hohn&U, 89; 
P. hector t model for female of 
P. polytm, 13, 52, 78; range 
of, 79 j characteristics of, 81 
flight of, 82 ; eaten by lizards, 
108 j eaten by birds, 110, 117 ; 
V. 6, 6a; P. Mppoaon, App. II ; 
P, logktuei, 27, 124, m 2; 
P. konido*, 29, VI. 3; P. 
fyaithoua, polymorpMsm in, 44 ; 
$ tyaithow, Xm. 4; $ ntnfc, 
Xin. 5; $ pwrvponius, XIII. 6; 
P. macarew, 23, 111; P. wew- 
non, 26, 89; P. tnendox, 24, 
61, n. 9; P. n&phalion, 44, 
Xm. 1 ; P. 0s|/w, XI. 8, 9 ; 
P. paradoxus, 25; P. #ow- 
8<mtas, 48, XI. 2 ; P. perrhebus, 
44, Xm. 3; P. pMlenor, as 
model, 40; taken by lizard, 
108 ; XVI. 1 ; P. polytes, poly- 
morphism in fernalos of, 13, 
75 ; mimic of Pharrnacophagus 
Papilio, 26 ; habits of, 52, 124 ; 
often more abundant than 
models, 56; description of, 
76-78; relative abundance of 
models in Ceylon, 79 ; breeding: 
experiments with, 84; equi- 
librium among females of in 
Ceylon, 90; relative abund- 
ance of three forms of female 
of in Ceylon, 97; historical 
notes on abundance of forms 
of female in Ceylon, 98 ,- origin 
of forma of female in, 1 25, 141 ; 
relation of polymorphic forms 
to models in, 149 note; preyed 
on by Wood-Swallow, 112; 
feeding experiments with, 116 ; 
V. 1-4, 1 a-4 a ; P. polyxenua, 
27; P. resc, App. II; P. rid- 
kycmua, 84, B6, VI. 8 ; P. 
ecerpedon, 110; P. troikia, 45, 



XVI. 2; P. a;en0ete, 23, 111, 
I. 4; P. zogrmtf, 48, X. 8 

Papilionidae, as mimics of Orien- 
tal models, 23-25; of African 
models, 29, 30, 35; of S. 
American models, 48; of N. 
American models, 45 

Parallel patterns, in different 
butterfly groups, 144 

Pareronia, 146, 149 ; P. ceylanica, 
23, 59, 116 note, 1. 1, 2 

Pattern and physiological pro- 
perties, possible connection be- 
tween, 137 

Patterns, overlapping series of in 
different groups of butterflies, 
145 

Pedaliodes, 136 

Pereute charops, 42, XI. 6, 7 

Pericopis, 39 

Perrhybns, as mimics of Ithp- 
mimes, coloration of male in 
P. malenka, 62; as members 
of mimicry rings, 134, 136; 
P. demophile, 151; P. lorena, 
161 ; P. mafanka, X. 4, 5, 6 

Pharmacophagus Swallow-tails, 
characteristics of, 22, App. H ; 
as models for Oriental butter- 
flies, 25 ; absence of in Africa, 
86; as models in S. America, 
48 ; as models in N. America, 45 

PJvngswa, 86 

Phyoipdes, 88, 54 

Physiological properties, possible 
connection of with pattern, 137 

Pieridae, as models for Oriental 
butterflies, 28; mimicry in 
African, 36; mimicry in S. 
American, 43; frequency of 
bird attacks on, 150 

Planema epaea, 35, VH. 6; P. 
macarista, sexual difference in, 
34, VII. 1, 2 ; mimicked by 
Btymniasphegea, 35; byPwwo- 
a&raea ewylua, 126; P, poggei, 
as model for plcmemoidea fe- 
male of PopiUo dordomta, 31 j 
P. jporograa, 126, TO 4; P. 
i, 126, VH. 3 



188 



INDEX 



ginctio work wft.li, 147 



_ trftiwjmrwioy in S. 

'American, 42 

flnridnivu*, 108 

rm birrl AM eornt of 
112 



J?oion - waters, x Pliarmaco- Ray, on adaptation, 4 6 

pluiguH HwaHow-tHilH Rodent** tM*aring on mimicry of 

PolyrnorphtHm, in fi*mftl(! of 
mimicking HpocicH, 13; among 
ftmali*H of /*. rtardanwt, 30 ; 
timcmg fomnh'H of /*. jmlyl&it 1R 

Population, condition* of tnjui- 
iibrimn in mixnd. U.I 

Poulton, 17; on N, American 
bultwfiicff, 4f>; cm th 

m*y group," 4 1 ; on Htit, 44, f2, AH 
fhrtitigh figtwy <f Hht'lfnrtl, M not** 
migratory limits 3 ; tin //y/w- H. Amc>rimut buttc^rflim, mimicry 
limnatt miftppwt, BO nci<; on mtiung, 38 

tto n^ltttion tw?twc*en mimetic H|Mrt-s, iw foundntion of mimntic 
fornuHi of /*. ptttj/tajs, IM>; on n^Wiinbiancim, 70, fti, 143 

prfKlatHHittM tiwH*tii, 10f; tin Hwit'|K*iw **xp*ritiwnte on 91 
mltttivw proportion of differimt KwynM*ru, on conUtntu of 
fornut of Pmiidlmnmft mrytitM, ntomm'hM of birtts, 1 14 

127; on local variation in 
1), chryttipputi 182 Tfjifttui tnmguinxt, 'Ml 

Frrl f 111, 122, 131; I*. ortw Teria* frrsfiftkt f 3ft; T, hfrabe, 110 
dirnorphium in, 131, Tkyrulia t 40, HIV. 8 



Vt 11, 18 

?n>, 110; /*. "te 



. 10 



with 



**Trfm*ry group/' in 8. 

Ameritm, 39 
Tritfiett, ii nttmitfry fn African 

butterfikw, 13 

, 121 



03 



difficulty of 



1K 

iblanc<, 8 
mintit*M cf Itbo> 

an icmlM-*r cif 
mitnk'ry ringn, 134, 13fi, 13Bj 
/*. (ithrtrmths, X. 9 
Ptmulttmttm, 11 1* 144; P. 6* 
dumti, 34* VI, 5{ I*. eurytug t 
n^lativn proportion of different 
fortiw in, ill i polymorphism 
of iti l*t40n to moditf, 148 
note j vsr, is mimie of 

fatfito t 35, 127, 
VH* 7 1 vw term, a mimics 
of JPftmtma teHtu, Iti, VH. 8 } 

var. o&ta^m an mimic of Fla Witmlng eoteuw, 10, 11 
nttnct 



Wittl*, on rt'ltttive abttndanoo of 
th thww forrfw of I J , in 

Coyloa, 99 

, on mimicry in Oriental 
on th oon- 
of tniniiory, SO; on the 
of P. jHttt/tM, 76 j on 
initial variUon, 



nxmrao 



ac,4. AY